<PAGE>


                                                                    EXHIBIT 10.2

                          SECOND AMENDED AND RESTATED
                   STOCK RESTRICTION AND BUY-SELL AGREEMENT
                   ----------------------------------------

     This Second AMENDED AND RESTATED STOCK RESTRICTION AND BUY-SELL AGREEMENT
is made as of the 3rd day of March, 2001 by and among John C. Sloan ("Sloan"),
Jorge Andrade ("Andrade"), and Howard Buffett ("Buffett"), and The GSI Group,
Inc., a Delaware corporation (the "Corporation").

                                   RECITALS
                                   --------
     The Shareholders are owners and holders of all of the issued and
outstanding voting common stock of the Corporation.

     As of the date hereof, the outstanding voting stock of the Corporation is
held as follows:

        Name                 Number of Shares
        ----                 ----------------

        Sloan                   1,195,000
        Andrade                   300,000
        Buffett                    80,000

     The parties hereto believe that in the interest of their continued success,
it is desirable to maintain continuity in the management, policies and ownership
of the Corporation, to provide for the purchase of Shares upon the occurrence of
certain contingencies, and to provide certain other agreements as more fully set
forth herein.  In connection therewith, the parties hereto wish to amend and
restate the Amended and Restated Stock Restriction and Buy-Sell Agreement to
which they may be parties, as provided below.

     NOW, THEREFORE, for and in consideration of the above premises and the
mutual covenants and agreements hereinafter contained, and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereby agree as follows:

                                   ARTICLE 1

                   INCORPORATION OF RECITALS AND DEFINITIONS
                   -----------------------------------------

     1.1  Incorporation of Recitals.  The Recitals are incorporated herein and
          -------------------------
constitute covenants, representations, and warranties of the Shareholders.

     1.2  Definitions.  For purposes of this Agreement:
          -----------

     (a) The term "and/or" shall mean one or the other or both, or any one or
more or all, of the things or persons in connection with which the conjunction
is used.

     (b) The term "Remaining Shareholders" shall mean the Shareholders either
(i) with respect to an Offer (as defined in Section 3.1), whose shares are not
the subject of such Offer
<PAGE>


under Article 3 hereof; or (ii) whose Shares are not the subject of a purchase
pursuant to Article 4 hereof.

     (c) The term "Requisite Vote" shall mean:  (i) at any time that there are
two (2) Shareholders or less, the affirmative vote of the Shareholder owning
more than fifty percent (50%) of the outstanding Shares entitled to vote at a
duly called and held meeting of the Shareholders; and (ii) at any time that
there are three (3) or more Shareholders, the affirmative vote of the
Shareholders owning more than fifty percent (50%) of the outstanding Shares
entitled to vote at a duly called and held meeting of the Shareholders, provided
that the matter under consideration shall have also received the affirmative
vote of all Shareholders owning Shares entitled to vote, except for any one (1)
Shareholder.

     (d) The term "Shares" shall mean all shares of the Corporation's common
stock, whether voting or non-voting, including, but not limited to, newly
authorized shares, shares issued out of authorized but unissued stock, shares
issued or credited in connection with any stock dividend, stock split or other
capital readjustment, as well as any voting trust certificates (there being none
at this date) representing any shares of stock issued by the Corporation and
owned by the Shareholder which are part of any voting trust or similar
agreement.

     (e) The term "Shareholders" and/or "Shareholder" shall mean Sloan, Andrade,
and Buffett and/or any other person or entity that at any time may become a
party hereto by reason of his or its ownership of Shares.

     (f) The term "Event" shall mean an event which triggers the right to
purchase or sell Shares hereunder and shall specifically refer to:

          (i)    the death of a Shareholder;

          (ii)   the termination of employment of a Shareholder,

          (iii)  the Effective Date of Permanent Disability or

          (iv)   the delivery by the Offering Shareholder of a Notice of an
     Offer (as such terms are defined in Section 3.1 below).

                                   ARTICLE 2
                            RESTRICTIONS ON SHARES
                            -----------------------

     2.1  Prohibition on Transfer.  Except as (i) expressly permitted herein;
          -----------------------
(ii) provided for in the Contribution Agreement, dated as of June 6, 1996, by
and among the Shareholders and John Funk (the "Contribution Agreement"); or
(iii) provided in the Stock Purchase Agreement, dated as of March 18, 1999, by
and among the Shareholders, John Funk and the Corporation (the "Stock Purchase
Agreement"), a Shareholder shall not at any time sell, pledge, hypothecate,
transfer, encumber, assign, give away, or in any way dispose of any Shares now
owned or hereafter acquired by him, nor shall such Shares be transferable,
voluntarily or involuntarily, by operation of law or otherwise, except in strict
compliance with the covenants, terms, and
<PAGE>


conditions set forth in this Agreement. Any attempt to do so in violation of
this Agreement shall not be recognized by the Corporation and shall be null and
void and of no force or effect whatsoever.

     2.2  Follow Along Rights and Obligations.  Notwithstanding the restrictions
          -----------------------------------
set forth in Sections 2.1 or 2.4 hereof, the Shareholder(s) owning more than
fifty percent (50%) of the outstanding Shares entitled to vote ("Controlling
Shareholders") may elect at any time to:

     (a) sell all, but not less than all, of their respective Shares, without
first having to comply with the provisions of this Agreement, provided that:

          (i)   the Shareholders other than the Controlling Shareholders (the
     "Noncontrolling Shareholders") shall have the right to participate in such
     sale on the same terms and conditions, including, without limitation,
     price, as those which pertain to the Shares being sold by the Controlling
     Shareholder(s); and

          (ii)  the Controlling Shareholder(s) shall have the right to require
     that the Noncontrolling Shareholders sell their Shares on the same terms
     and conditions, including, without limitation, price, as those which
     pertain to the Shares being sold by the Controlling Shareholders.

     (b) cause the Corporation to register its Shares under the Securities Act
of 1933, as amended, in a bona fide underwritten public offering (a "Public
Offering").

     2.3  Legend on Certificates.  The Corporation shall cause to be placed on
          ----------------------
each certificate of its Shares which may now or hereafter be issued to a
Shareholder (except certificates evidencing Shares sold free of the restrictions
of this Agreement), a notice in the following form:

          "The shares of stock evidenced by this Certificate are subject to the
     terms and conditions of a Stock Restriction and Buy-Sell Agreement among
     the Corporation and certain of its shareholders (the "Agreement").  Copies
     of the Agreement are on file at the offices of the Corporation, reference
     to all the terms and conditions thereof being hereby made.  No sale or
     transfer of the Shares evidenced hereby may be effected, except pursuant to
     the terms and conditions of the Agreement."

If such legend is placed on the reverse side rather than the face of any such
certificate, there shall be placed on the face of such certificate a legend in
the following form:

     "For restrictions on transfer, see notice on reverse side hereof."

     2.4  Wrongful Transfer.  Subject to Sections 2.1 and 2.2 hereof, no sale,
          -----------------
pledge, hypothecation, transfer, encumbrance, assignment, gift or other
disposition by a Shareholder of any of his Shares shall be effective, unless and
until:  (i) he has first complied with all the provisions of this Agreement, and
(ii) his transferee shall take such Shares subject to the terms of this
Agreement, and shall agree in writing to become a party to this Agreement as a
Shareholder
<PAGE>



and be bound by all of the terms, conditions and provisions hereof. If a
Shareholder fails to comply with this Agreement, the Corporation shall have the
right to compel such Shareholder or any transferee to transfer and deliver his
Shares in accordance with the provisions of this Agreement.

     2.5  Maintenance of S Corporation Status.
          -----------------------------------

     (a) Each Shareholder agrees that he will take all action necessary to
permit the Corporation to retain its tax status as an S Corporation ("S
Corporation") under Subchapter S (Section 1361 et seq.) of the Internal Revenue
Code of 1986, as amended (the "Code"), including, but not limited to, the
execution and delivery of any and all consents and other documents required at
any time for the continuance of S Corporation status, or required to carry out,
effectuate, implement or exercise any and all other elections available to, or
powers exercisable by, a corporation having elected S Corporation status.
Except as otherwise specifically provided in this Agreement, the Shareholders
shall not take any action which will cause the Corporation not to be taxed as an
S Corporation.

     (b) Subject to the limitations of the Delaware General Corporation Law (the
"DGCL"), as long as the Corporation remains an S Corporation, the Shareholders
agree to take all actions necessary to cause the directors of the Corporation to
declare and pay to the Shareholders dividends each year in an amount not less
than all federal and state income taxes, including but not limited to estimated
tax payments, payable by the Shareholders each year with respect to the income
of the Corporation, based upon the maximum marginal federal and state individual
income tax rates applicable to any Shareholder.

     (c) Upon any transfer of the Shares permitted hereunder, the Corporation
may require arrangements reasonably satisfactory to it to assure that any
transferee shall take any and all action necessary or desired to allow the
Corporation to maintain S Corporation status (including, without limitation,
with respect to any transfer in trust, the timely filing of an election to treat
such trust as a qualified Subchapter S Trust under Section 1361(d) of the Code).

                                   ARTICLE 3

                  PURCHASE OF SHARES - RIGHT OF FIRST REFUSAL
                 --------------------------------------------

     3.1  Notice of Transfer.  If a Shareholder (the "Offering Shareholder")
          ------------------
receives during his lifetime any bona fide offer in cash and/or marketable
securities (an "Offer") to sell or otherwise transfer any or all of his Shares
or the right to vote said Shares, or any combination thereof (the "Offered
Shares") to any person or entity, the Offering Shareholder shall give at least
sixty (60) days prior written notice to the Corporation and the Remaining
Shareholders of his intention to so transfer his Shares (the "Notice").  The
Notice shall state (i) the number of Offered Shares; (ii) the name, business and
residence address of the proposed transferee (the "Transferee");  (iii) the
consideration, if any, to be paid for the Offered Shares, which consideration
shall be in the form of cash and/or marketable securities (the "Offered Price");
(iv) the date upon which the proposed transfer to the Transferee is to be
consummated; and (v) all
<PAGE>



other material terms of the proposed transfer. A copy of any written agreement
(whether executed or not) evidencing the Offer shall be attached to the Notice.

     3.2  Rights of First Refusal.  From and after the date of the Notice (the
          -----------------------
"Notice Date"), the Corporation and the Remaining Shareholders shall have
options to purchase the Offered Shares, upon the terms set forth in Section 3.3
hereof, exercisable in the order of priority and within the time periods set
forth below, provided, however, that unless the exercise of the option(s) set
forth in this Section 3.2 result in the purchase, in the aggregate, of all of
the Offered Shares, the exercise of such option(s) shall be null and void.

     (a) For a period of thirty-five (35) days after the Notice Date (the
"Corporation's Option Period"), the Corporation shall have the option to acquire
all or any portion of the Offered Shares (the "Corporation's Option").  The
Corporation shall exercise the Corporation's Option, if at all, by giving
written notice to that effect to the Offering Shareholder and the Remaining
Shareholders within the Corporation's Option Period.

     (b) For a period of twenty-five (25) days following the first to occur of
(i) the expiration of the Corporation's Option Period without the Corporation
exercising its option or (ii) the Corporation's written notice to the Offering
Shareholder and the Remaining Shareholders that it will not purchase any or all
of the Offered Shares (the "Remaining Shareholders' Option Period"), the
Remaining Shareholders shall have the option to acquire all of the Offered
Shares not being purchased by the Corporation (the "Remaining Shareholders'
Option").  In the event that more than one of the Remaining Shareholders
exercises the Remaining Shareholders' Option, then unless otherwise agreed, each
such Remaining Shareholder must purchase that percentage of the Offered Shares
not being purchased by the Corporation equal to his proportionate ownership of
the shares owned by all of the electing Remaining Shareholders.  Each Remaining
Shareholder shall exercise the Remaining Shareholders' Option, if at all, by
giving written notice to that effect to the Corporation, the other Remaining
Shareholders, and the Offering Shareholder within the Remaining Shareholders'
Option Period.

     3.3  Purchase Price and Terms.  In the event the Corporation's Option
          ------------------------
and/or the Remaining Shareholders' Option is exercised, the party(ies)
exercising such option(s) shall purchase the Offered Shares at a price (in cash
and/or marketable securities) equal to the cash value of the Offered Price
(determined as of the date of the closing), upon the same terms and conditions
provided in the Notice, provided that the closing of such purchase shall occur
in the manner described in Section 7.2(a) hereof.

     3.4  Failure to Exercise the Corporation's and Remaining Shareholder's
          -----------------------------------------------------------------
Right of First Refusal Options.  If the Corporation and the Remaining
------------------------------
Shareholders fail to exercise their respective Options in accordance with
Section 3.2 hereof to purchase in the aggregate all of the Offered Shares, the
Offered Shares may be transferred to the Transferee as provided in the Notice.
The effectiveness of such transfer is conditioned upon the Transferee agreeing
in writing to be a party to this Agreement as a Shareholder and to be bound by
all of the terms, conditions and provisions hereof.  If the transfer does not
occur in accordance with the terms disclosed in the Notice, such transfer shall
be automatically null and void without any further action being required on the
part of the Corporation or the Remaining Shareholders, and any attempt to
<PAGE>



transfer the Offered Shares thereafter without first complying with the terms of
this Article 3 shall be deemed a wrongful transfer within the meaning of Section
2.4 hereof.

                                   ARTICLE 4

                              PURCHASE OF SHARES
                              -------------------

     4.1  Purchase Upon Death of Shareholder.  Upon the death of a Shareholder
          ----------------------------------
(the "Decedent"), the Shares owned by the Decedent (the "Decedent's Shares")
shall be subject to the following rights and obligations:

     (a) For a period of forty-five (45) days after the death of the Decedent
(the "Remaining Shareholder's Purchase Option Period" in this Section 4.1 only),
the Remaining Shareholders shall have the option to purchase any or all of the
Decedent's Shares from the Decedent's legal representative (the
"Representative") at the price and on the terms set forth in Articles 5, 6 and 7
hereof (the "Remaining Shareholder's Purchase Option").  In the event that more
than one of the Remaining Shareholders elects to purchase the Decedent's Shares,
then unless otherwise agreed by the Remaining Shareholders, each electing
Remaining Shareholder must purchase that percentage of the Decedent's Shares
(each, a "Respective Percentage") equal to his proportionate ownership of the
Shares owned by all of the electing Remaining Shareholders.  Each Remaining
Shareholder shall exercise the Remaining Shareholder's Purchase Option, if at
all, by giving written notice to that effect to the Corporation, the other
Remaining Shareholders and the Representative within the Remaining Shareholder's
Option Period.

     (b) In the event the Remaining Shareholders do not exercise their Purchase
Options with respect to all of the Decedent's Shares, the Representative shall
hold the Decedent's Shares not so purchased subject to the terms, conditions and
provisions of this Agreement.

     (c) Notwithstanding anything in Subsections 4.1(a) and 4.1(b) above, if the
Trustee of a Trust (as defined in Section 6.5 hereof), of which the Remaining
Shareholders are grantors, is the beneficiary of any Policies (as defined in
Section 6.5 hereof) on the Decedent's life, the Remaining Shareholders shall
have the obligation to purchase, each in proportion to his Respective
Percentage, so much or all of the Decedent's Shares as would exhaust the
insurance proceeds from the Policies.  To the extent that the insurance proceeds
from the Policies exceed the aggregate Purchase Price (as defined in Section 5.1
hereof) of the Decedent's Shares, the Remaining Shareholders shall contribute,
pro rata to their respective ownership of voting Shares (after having acquired
the Decedent's Shares), such excess proceeds to the capital of the Corporation.
In the event the insurance proceeds from the Policies are less than the
aggregate Purchase Price of the Decedent's Shares, the remaining Shares shall be
subject to the rights and obligations set forth in Subsections 4.1(a) and
4.1(b).

     4.2  Purchase Upon Permanent Disability of Shareholder.  If a Shareholder
          -------------------------------------------------
becomes Permanently Disabled (a "Disabled Shareholder" as defined below), the
Shares owned by the Disabled Shareholder shall be subject to the following
rights and obligations:
<PAGE>



     (a) For a period of 18 months following the Effective Date of Permanent
Disability (as defined below) of the Disabled Shareholder, the Disabled
Shareholder shall have the right, through designated representatives or
otherwise, to solicit offers to purchase his Shares, which offers, if any, shall
be subject to the provisions of Article 3 of this Agreement.

     (b) For a period of twelve (12) months following the first to occur of:
(i) the expiration of the 18 month period described in subsection 4.2(a) above
without receipt of an Offer (as defined in Section 3.1), or (ii) written notice
to the Corporation and the Remaining Shareholders that the Disabled Shareholder
has elected to terminate the 18 month period described in subsection 4.2(a)
above, the Corporation shall have an option to purchase any or all of the
Disabled Shareholder's Shares at the price and on the terms set forth in
Articles 5, 6 and 7 hereof.  The Corporation shall exercise its option, if at
all, within the aforesaid Corporation's option period upon written notice to the
Remaining Shareholders and to the Disabled Shareholder or his legal
representative.

     (c) For a period of ninety (90) days the first to occur of:  (i) the
expiration of the 12 month period described in subsection (b) above, or (ii)
written notice to the Disabled Shareholder or his legal representative and to
the Remaining Shareholders that the Corporation does not intend to purchase any
or all of the Disabled Shareholder's Shares, the Remaining Shareholders shall
have an option to purchase any or all of the Disabled Shareholder's Shares at
the price and on the terms set forth in Articles 5, 6 and 7 hereof (a "Call
Option").  In the event that more than one of the Remaining Shareholders elects
to purchase the Disabled Shareholder's Shares, then unless otherwise agreed by
the Remaining Shareholders, each electing Remaining Shareholder must purchase
that percentage of such Disabled Shareholder's Shares equal to his proportionate
ownership of the Shares owned by all of the electing Remaining Shareholders.
Each Remaining Shareholder shall exercise his Call Option, if at all, within the
aforesaid Remaining Shareholders' option period upon written notice to the
Corporation, the other Remaining Shareholders, the other Remaining Shareholders,
and the Disabled Shareholder or his legal representative.

     (d) In the event the Remaining Shareholders and the Corporation do not
exercise their options with respect to all of the Disabled Shareholder's Shares,
the Disabled Shareholder or his legal representative, as the case may be, shall
hold the Disabled Shareholder's Shares not so purchased subject to the terms,
conditions and provisions of this Agreement.

     4.3  Definition of Permanent Disability.  A Shareholder shall be deemed to
          ----------------------------------
be "Permanently Disabled" upon the first to occur of the following events:

     (a) if by reason of injury, sickness or other incapacity he is unable, for
a period of six (6) consecutive months or for any six (6) months during a nine
(9) consecutive month period, to discharge his regular duties and
responsibilities as an employee, officer and/or director of the Corporation.  If
the parties shall at any time be unable to agree on whether a Shareholder is or
has been so disabled, the Corporation and the Shareholder shall promptly and
jointly appoint a medical doctor; or if they are unable to so agree, they shall
each promptly appoint a medical doctor to make such determination, and the
collective decision of such medical doctors shall be binding on all parties
hereto.  If such doctors are unable to agree, they shall promptly appoint a
<PAGE>



third medical doctor to make such determination, and the decision of such third
medical doctor shall be binding on all parties hereto; or

     (b) the failure or refusal of a Shareholder to submit to any examination or
to appoint a medical doctor pursuant to subsection (a) of this Section 4.3
within sixty (60) days after the date on which the Shareholder receives a
written notice from the Remaining Shareholders to do so; or

     (c) the adjudication of such Shareholder as an incompetent or a disabled
person by a court of competent jurisdiction.

     4.4  Definition of Effective Date of Permanent Disability.  If a
          ----------------------------------------------------
Shareholder is deemed to be Permanently Disabled pursuant to Section 4.3 hereof,
then the "Effective Date of Permanent Disability" shall be the first to occur of
the following:

     (a) the date upon which the examining doctor(s) determine(s) that the
Shareholder is Permanently Disabled; or

     (b) the sixtieth (60th) day immediately succeeding the day on which a
Shareholder receives a written notice from the Corporation to submit to an
examination pursuant to Section 4.3(a) hereof, if the Shareholder fails or
refuses to submit to such examination or fails or refuses to appoint a medical
doctor; or

     (c) the sixtieth (60th) day immediately succeeding the date of the
adjudication described in Section 4.3(c) hereof, unless prior to the expiration
of such period the adjudication has been reversed, vacated, or overruled; or

     (d) the first day of the seventh (7th) consecutive month or the first day
of the seventh (7th) month during any nine (9) consecutive month period of the
Shareholder's inability to perform his regular duties and responsibilities as an
employee, officer, and/or director of the Corporation as a result of his injury,
sickness, or other incapacity.

     4.5  Purchase Upon Termination of Employment of Shareholder.  If a
          ------------------------------------------------------
Shareholder's employment by the Corporation terminates (a "Terminated
Shareholder"), the Shares owned by the Terminated Shareholder shall be subject
to the following rights and obligations:

     (a) For a period of twelve (12) months following the last date of
employment of the Terminated Shareholder the Corporation shall have an option to
purchase any or all of the Terminated Shareholder's Shares at the price and on
the terms set forth in Articles 5, 6 and 7 hereof.  The Corporation shall
exercise its option, if at all, within the aforesaid Corporation's option period
upon written notice to the Remaining Shareholders and to the Terminated
Shareholder.

     (b) For a period of ninety (90) days following the first to occur of:  (i)
the expiration of the 12 month period described in subsection 4.5(a) above
without the Corporation exercising its option to purchase all of the Terminated
Shareholder's Shares, or (ii) written notice to the Terminated Shareholder and
the Remaining Shareholders that the Corporation does not intend to exercise its
option under subsection 4.5(a) above, the Remaining Shareholders shall have an
<PAGE>



option to purchase any or all of the Terminated Shareholder's Shares at the
price and on the terms set forth in Articles 5, 6 and 7 hereof (a "Call
Option").  In the event that more than one of the Remaining Shareholders elects
to purchase the Terminated Shareholder's Shares, then unless otherwise agreed by
the Remaining Shareholders, each electing Remaining Shareholder must purchase
that percentage of such Terminated Shareholder's Shares equal to his
proportionate ownership of the Shares owned by all of the electing Remaining
Shareholders.  Each Remaining Shareholder shall exercise his Call Option, if at
all, within the aforesaid Remaining Shareholders' option period upon written
notice to the Corporation, the other Remaining Shareholders, and the Terminated
Shareholder.

     (c) In the event the Remaining Shareholders and the Corporation do not
exercise their options with respect to all of the Terminated Shareholder's
Shares, the Terminated Shareholder shall hold his Shares not so purchased
subject to the terms, conditions and provisions of this Agreement.

                                   ARTICLE 5

                      DETERMINATION OF THE PURCHASE PRICE
                     ------------------------------------

     5.1  Purchase Price.  The parties hereto recognize the problems relative to
          --------------
determining the value of the Corporation.  As a result, the parties hereto agree
that the purchase price (the "Purchase Price") for each Share to be purchased
pursuant to Article 4 hereof shall be Six and 34/100 Dollars ($6.34) per Share.
The Purchase Price shall be conclusive and binding on the parties hereto.

     5.2  Adjustments to Purchase Price.  The Shareholders may review and adjust
          -----------------------------
the Purchase Price once each year, in light of the audited financial results of
the Corporation as well as any other factors that, in the Shareholders'
judgement, are relevant in determining the Corporation's value; provided,
however, that for the purpose of calculating the Purchase Price with respect to
any Event that gives rise to a purchase under Article 4, the Purchase Price in
effect on the date of the Event shall control.

                                   ARTICLE 6

                PAYMENT OF THE PURCHASE PRICE AND OTHER MATTERS
               ------------------------------------------------

     6.1  Payment.  The Purchase Price for the Shares purchased pursuant to the
          -------
provisions of Article 4 shall be paid in full in cash at the closing, except
that at the option of each purchasing party, but in all events subject to
Section 6.5 hereof, up to seventy percent (70%) of the Purchase Price may be
deferred as provided herein, provided that at least thirty percent (30%) of the
Purchase Price is paid in cash at closing.  Notwithstanding the foregoing, if
the Event resulting in a sale of Shares is a Shareholder being terminated for
Cause (as defined below), up to ninety percent (90%) of the Purchase Price may
be deferred as provided herein, provided that at least ten percent (10%) of the
Purchase Price is paid in cash at closing. As used herein, "Cause" shall mean:
(i) commission of any dishonest act by a Shareholder in connection with his or
her employment by the Corporation or any act of willful misconduct which has
affected or can be
<PAGE>



reasonably expected to affect the business or reputation of the Corporation in a
materially adverse manner; (ii) diversion of any material corporate opportunity
of the Corporation for the Shareholder's direct or indirect benefit; or (iii)
commission by the Shareholder of any wrongful act which constitutes cause for
dismissal of a corporate officer or employee under applicable law.
Notwithstanding the previous sentence, if "Cause" is defined in the Terminated
Shareholder's Employment Agreement, the definition set forth in such Employment
Agreement shall apply for purposes of this Agreement.

     6.2  Promissory Note.  The deferred portion of the Purchase Price shall be
          ---------------
evidenced by a promissory note (the "Note") of the purchasing party made payable
to the order of the selling party.  The Note shall be in the form of Exhibit A
attached hereto and shall be dated as of the closing.  Except as otherwise set
forth below, the principal balance shall be paid over a time not exceeding sixty
(60) months and each installment of the principal balance shall include
interest, accruing from the date of the Note, at a rate announced from time to
time by the LaSalle Bank N.A. as its prime rate (the "Interest Rate"); provided,
however, that if the Event resulting in a sale of Shares is a Shareholder being
terminated for Cause, the principal balance shall be paid over a time not
exceeding one hundred twenty (120) months.  In all cases, the terms of payment
shall be those set forth in the attached Exhibit A.

     6.3  Collateral.  The Note shall be secured by a pledge of all of the
          ----------
Shares being purchased by any purchasing party other than the Corporation.  Any
and all documents reasonably necessary for purposes of perfecting a security
interest in all of the purchased Shares shall be executed by the purchaser
including a pledge agreement containing, among other provisions, a third party
escrow for the Shares.  Unless and until an Event of Default (as defined in the
Note) occurs, the purchaser of the Shares shall have all the rights of the owner
thereof, including, without limitation, the right to vote and the right to
receive dividends and other distributions.  Following an Event of Default, the
pledgee of the Shares shall have all the rights of the owner thereof, provided
that any dividends or distributions made pursuant to Section 2.5(b) of this
Agreement with respect to the fiscal year in which the Event of Default occurs
shall be allocated among the purchaser and pledgee of the Shares in the same
proportion as the tax liability with respect to the income of the Corporation is
allocated among them.

     6.4  Guaranteed Indebtedness.  If at the time of a purchase of Shares
          -----------------------
pursuant to Article 4 hereof, the Corporation has outstanding indebtedness which
is personally guaranteed by certain of the Shareholders ("Guaranteed Debt") (it
being understood by the Shareholders that Buffett shall not at any time
personally guarantee any such indebtedness), each of the Remaining Shareholders
who has personally guaranteed such indebtedness agrees to use his good faith
efforts to obtain the release of the selling Shareholder's personal guaranty of
the Guaranteed Debt, provided that (i) such Remaining Shareholders shall not be
required to offer a pledge of his residence or his spouse's guaranty in order to
secure such release, and (ii) such Remaining Shareholders' actual ability to
secure such release shall not be a condition of closing the sale and purchase
under Article 4 hereof.  Notwithstanding the foregoing, the Remaining
Shareholders shall have no duty or obligation to attempt to obtain the release
of a selling Shareholder who was terminated by the Corporation for Cause.

     6.5  Life Insurance Proceeds.
          -----------------------
<PAGE>



     (a) Notwithstanding anything to the contrary contained in Section 6.1
hereof, in the event the Shareholders are grantors of a trust (the "Trust"), the
trustee (the "Trustee") of which is the owner and beneficiary of one or more
insurance policies ("Policies") on the life of a Shareholder who owns Shares at
the time of his death (the "Deceased Shareholder"), the death benefits under the
Policies, net of applicable taxes on such proceeds, if any, shall be paid upon
the Trustee's receipt thereof as follows: (i) to the estate of the Deceased
Shareholder on account of the Purchase Price of the Shares on behalf of the
Remaining Shareholders pursuant to Subsection 4.1(c), and (ii) the balance of
such proceeds, if any, shall be paid to the Corporation as a contribution to
capital on behalf of the Remaining Shareholders pro rata to their voting Shares.

     (b) If at the time of death of a Former Shareholder (as defined below), the
Trustee is the owner and beneficiary of one or more Policies on the Former
Shareholder's life, the death benefits under the Policies, net of applicable
taxes on such proceeds, if any, shall be paid upon the Trustee's receipt thereof
as follows: (i) to the estate of the Former Shareholder as a prepayment of the
unpaid balance, if any, of the purchase price, plus accrued interest thereon,
then owed by any of the then-current Shareholders, either pursuant to this
Agreement or otherwise, for the Former Shareholder's Shares; and (ii) the
balance, if any, of such proceeds, or all such proceeds if no unpaid balance
described in clause (i) exists, shall be paid to the Corporation as a
contribution to capital on behalf of the then-current Shareholders pro rata to
their voting Shares. As used herein, the term "Former Shareholder" means any
person who previously owned voting Shares, but who, at the time of his death, no
longer owns Shares.

     6.6  Prepayment of Note.  If following the death of a Former Shareholder,
          ------------------
the Corporation receives from the Trustee or the Remaining Shareholders payment
(whether as a contribution to its capital or otherwise) of the proceeds of one
or more Policies on the life of the Former Shareholder, the Corporation shall
upon receipt of such proceeds prepay to the extent thereof the unpaid balance,
if any, of principal plus accrued interest under any outstanding Note payable by
the Corporation to the estate or heirs of the Former Shareholder executed in
connection with the purchase of the Former Shareholder's Shares.

                                   ARTICLE 7

                                  THE CLOSING
                                  -----------

     7.1  Location.  Unless otherwise agreed by the parties, the closing of the
          --------
sale and purchase of the Shares under Article 3 or 4 hereof shall take place at
the Corporation's principal headquarters office.

     7.2  Time.
          ----

     (a) Article 3 Transfer.  In the case of a purchase of Shares under Article
3, the closing shall take place in accordance with the terms of the Notice,
provided that the closing shall not take place earlier than thirty (30) days
after the latest to occur of (i) the expiration of the last option which may be
exercised with respect to the Offering Shareholder's Shares; or (ii) with
respect to the Corporation only, the earliest date on which the Corporation is
permitted to
<PAGE>



purchase the Shares pursuant to the terms of (x) the Indenture, dated as of
November 1, 1997, between the Corporation and LaSalle National Bank, as trustee,
relating to the $100 million aggregate principal amount 10-1/4% Senior
Subordinated Notes due 2007 (the "Indenture"), and (y) any other material
financing agreement.

     (b) Article 4 Transfer.  In the case of a purchase of Shares under Article
         ------------------
4, the closing shall take place within thirty (30) days after the latest to
occur of: (i) the Trustee's receipt of death benefits from a Policy (as defined
in Subsection 6.5(a) hereof); (ii) the expiration of the last option which may
be exercised with respect to the Shares to be acquired by the purchasing party
or parties; or (iii) with respect to the Corporation only, the earliest date on
which the Corporation is permitted to purchase the Shares pursuant to the terms
of the Indenture and any other material financing agreement.

     (c) Restricted Purchase.  Notwithstanding anything else contained in
         -------------------
Article 4 hereof, it is the intention of the parties hereto that the provisions
of Subsections 7.2(a)(ii) and 7.2(b)(iii) be interpreted to postpone the closing
of purchases by the Corporation only to the extent required by the Indenture or
other material financing agreement, and that the Corporation close all of the
purchases of Shares for which it has exercised options as expeditiously as
possible. Accordingly, in the event the Corporation is not permitted to close
the purchase of all Shares for which it has exercised an option, the Corporation
shall purchase as many Shares for which it has exercised options as may be
permitted by the Indenture or other financing agreement, as otherwise provided
in this Section 7.2, and shall thereafter acquire any remaining such Shares for
which it has exercised an option in one or more additional closings to be held
within thirty (30) days of first being permitted to acquire any such additional
Shares pursuant to the Indenture or other financing agreement. Notwithstanding
the foregoing, the Corporation shall not be required to close the purchase of
Shares with respect to any specific Representative, Disabled Shareholder, or the
Terminated Shareholder more than once each fiscal quarter. Further, in the event
the Corporation is obligated to purchase Shares from more than one holder
thereof (including holders of nonvoting stock) in a given fiscal quarter and is
restricted in its ability to do so as a result of the Indenture or other
financing agreement, the Corporation shall allot the number of shares of stock
that it is able to purchase within any given fiscal quarter pro rata based on
the total number of Shares that would have been purchased by the Corporation as
a result of such Events had the Indenture or other financing agreement
restrictions not been in effect. Restrictions applicable to the Corporation
shall not affect the timing of the closing of any purchase of Shares by any
other party.

     7.3  Execution and Delivery of Documents.  Upon the closing of the sale and
          -----------------------------------
purchase, the selling Shareholder, the Corporation and the Remaining
Shareholders shall execute and deliver to each other the various documents which
shall be required to carry out their undertakings hereunder, including, without
limitation, the payment of cash and the execution and delivery of the Note and
any collateral instruments.

     7.4  Resignation as Officer and/or Director.  Upon the closing of the sale
          --------------------------------------
and purchase of Shares under Article 3 or 4 hereof, the selling Shareholder
shall resign as an officer and/or director of the Corporation.
<PAGE>



                                   ARTICLE 8

                             CORPORATE GOVERNANCE
                             --------------------

     8.1  Shareholder Approval for Significant Corporate Matters.
          ------------------------------------------------------
Notwithstanding any provision contained in the Certificate of Incorporation, the
By-Laws of the Corporation, any other agreement between the Shareholders and the
Corporation or under the DGCL, for so long as Sloan, Andrade or Buffett are
Shareholders, the unanimous vote of the Shareholders shall be required in
connection with the following matters ("Significant Corporate Matters"), except
as expressly provided below:

     (a) any adjustments to the Purchase Price of Shares pursuant to Section 5.2
hereof;

     (b) the liquidation, dissolution, recapitalization or reorganization of the
Corporation in any form of transaction;

     (c) the authorization or issuance of any securities of the Corporation,
including any Shares, rights, options, warrants, debt securities, derivative
securities or securities that are convertible into other securities; provided,
however, that in the event additional Shares are to be authorized in connection
with a Public Offering, then such authorization and issuance shall only require
the approval of the holders of more than fifty percent (50%) of the outstanding
Shares entitled to vote;

     (d) the termination of the election to be treated as an S Corporation under
the Code.

     (e) the acquisition or divestiture of any business segment or asset which
alone, or in the aggregate, has value in excess of $250,000, excluding, however,
the sale of substantially all of the business and/or assets of the Corporation,
which shall only require the approval of the holders of more than fifty percent
(50%) of the outstanding Shares entitled to vote;

     (f) the adoption or approval of a stock option or equity based incentive
plan for the benefit of employees of the Corporation;

     (g) the exercise by the Corporation of any option or other right to
purchase shares under any plan described in Subsection (f) above; and

     (h) any amendment to the Certificate of Incorporation or By-Laws of the
Corporation.

     8.2  Shareholder Approval of Other Corporate Matters.  All matters which
          -----------------------------------------------
under the DGCL, the Certificate of Incorporation or the By-Laws of the
Corporation require Shareholder approval, but do not involve any Significant
Corporate Matters, shall require the affirmative vote of the holders of more
than fifty percent (50%) of the outstanding Shares entitled to vote.

     8.3  Board of Directors.  The Board of Directors of the Corporation shall
          ------------------
consist of three (3) persons, which number may be increased by unanimous vote of
the then-existing directors. The vacancy resulting from the death, resignation,
or removal of a director shall be filled by the unanimous decision of the
directors then in office. Any director elected to fill a
<PAGE>



vacancy shall have the same remaining term as that of his predecessor. At the
next election, the position shall be filled by the unanimous decision of the
Shareholders and until such decision is reached, that Board seat shall remain
vacant. Notwithstanding the foregoing, each of the Shareholders entitled to vote
to elect the directors of the corporation agree to cast their votes and take any
other necessary action so that, for so long as any of Sloan, Andrade or Buffett
is both a Shareholder and an officer of the Corporation, such person shall be
elected as a director. Moreover, each of the Shareholders entitled to vote to
elect the directors of the Corporation agree to cast their votes and take any
other necessary action so that, for so long as any of Sloan, Andrade or Buffett
is a Shareholder or an officer of the Corporation, such person shall be elected
as a director, unless the Shareholders, by Requisite Vote, determine that such
person shall not be eligible to serve as a director of the Corporation.

     8.4  Approval of Certain Matters by Board of Directors.  In addition to and
          -------------------------------------------------
not in limitation of any provision of the Corporation's Certificate of
Incorporation, By-Laws or the DGCL, the following actions by the Corporation
shall require the unanimous approval of the Board of Directors:

     (a) making any capital expenditures in any given fiscal year which, in the
aggregate, exceed the budgeted amount for capital expenditures for that fiscal
year as approved by the Board;

     (b) entering into operating leases in any given fiscal year that exceeds
$250,000.

     (c) removal or significant change in the duties and responsibilities of an
officer who is also a Shareholder;

     (d) declaration of a stock or cash dividend;

     (e) the payment of any directors fees;

     (f) exercise of any option or other right of purchase under this Agreement;

     (g) incurring, guaranteeing or otherwise becoming liable for indebtedness
for borrowed money in an amount in excess of $500,000, or any action to prepay
any existing indebtedness by an amount in excess of $500,000;

     (h) the determination to change the Corporation's independent auditing
firm; and

     (i) the decision to employ any person or terminate the employment of any
employee of the Corporation having an annual salary of greater than $85,000.00;
provided, however, that when considering the termination of the employment of
any Shareholder, such Shareholder shall abstain from and not be entitled to vote
on such decision, and unanimity shall be determined without consideration of
such Shareholder.
<PAGE>



                                   ARTICLE 9

                           TERMINATION OF AGREEMENT
                           -------------------------

     9.1  Events Causing Termination.  This Agreement and all restrictions on
          --------------------------
transfer created hereby shall terminate on the occurrence of any of the
following events:

     (a) Upon the adoption of a plan of dissolution of the Corporation, provided
such plan is carried out diligently and all assets remaining after payment of or
provision for liabilities are distributed to the Shareholders within a
reasonable time thereafter; or

     (b) The execution of a written instrument to that effect signed by
Shareholders owning all of the outstanding Shares entitled to vote; or

     (c) Permanent cessation of the business of the Corporation; or

     (d) The sale of substantially all of the assets or business of the
Corporation; or

     (e) A single Shareholder becoming the legal and beneficial owner of all
then issued and outstanding Shares; or

     (f) The consummation of a Public Offering.

     9.2  Effect of Termination.  The termination of this Agreement for any
          ---------------------
reason shall not effect any right or remedy accrued hereunder prior to the
effective date of such termination.

                                  ARTICLE 10

                                 MISCELLANEOUS
                                 -------------

     10.1  Piggy-back Registration Rights.  The Corporation agrees that, at any
           ------------------------------
time during the term of this Agreement, if the Corporation shall seek a Public
Offering, each Shareholder shall be notified and shall be entitled to elect to
have included in such proposed registration, without cost or expense, such
number of Shares as the underwriter for the offering shall permit; provided,
however, that in the event the underwriter shall permit less than all of the
Shares to be registered, the number of Shares included in such registration
shall be reduced on a pro rata basis among the Shareholders (the "Piggy-Back
Rights"). In the event of such a proposed registration, the Corporation shall
furnish the Shareholders with no less than thirty (30) days written notice prior
to the proposed filing of the registration statement. Such notice shall continue
to be given by the Corporation to such Shareholders for each proposed
registration by the Corporation until such time as all of the Shares have been
registered. Such Shareholders shall exercise their Piggy-Back Rights by giving
written notice within twenty (20) days of the receipt of the Corporation's
notice of intention to file a registration statement.

     10.2  Effect of Improper Transfer.  Except as otherwise permitted under the
           ---------------------------
Contribution Agreement, if a transfer or attempted transfer violates any
provision of this Agreement, or if the transferor, after the transfer,
reacquires all or any portion of the transferred
<PAGE>



Shares, such transfers or attempted transfers shall be null and void and the
Shares transferred or attempted to be transferred shall remain subject to this
Agreement as if no transfer had been made.

     10.3  Voting of Shares.  The Representative, Disabled Shareholder, Disabled
           ----------------
Shareholder's legal representative, Offering Shareholder, or Terminated
Shareholder shall have no vote regarding any given option of the Corporation to
purchase Shares under this Agreement.

     10.4  Entire Agreement.  Except for the Contribution Agreement and the
           ----------------
Stock Purchase Agreement, the terms and conditions contained herein are the full
and complete terms of the agreement between the parties hereto regarding the
subject matter hereof and supersede any and all prior agreements by and among
the Corporation and the Shareholders concerning the ownership, sale or other
disposition of the Shares including, without limitation, any Stock Restriction
and Buy-Sell Agreement dated prior to the date hereof with respect to the Shares
to which the Corporation and the Shareholders may be parties, and any Stock
Restriction and Cross Purchase Agreement, dated June 6, 1996, as amended or
restated from time to time by and among the Shareholders. No alterations,
amendments, or modifications of such terms shall be binding on the parties
hereto unless reduced to writing and approved by all of the Shareholders.

     10.5  Binding Effect.  This Agreement shall be binding not only upon the
           --------------
parties hereto, but upon their respective heirs, legal representatives,
successors, and assigns. All persons bound hereby shall execute such instruments
and perform such acts as may be reasonably necessary or desirable to effectuate
the terms and provisions of this Agreement.

     10.6  Adoption by Corporation.  The Shareholders hereto will cause the
           -----------------------
Board of Directors to adopt appropriate minutes and resolutions recognizing,
confirming, ratifying, and adopting the terms of this Agreement and any
amendments to the By-Laws consistent with the provisions herein.

     10.7  Reference in Will.  Each Shareholder shall make reference to this
           -----------------
Agreement in any will or codicil that he may hereafter execute and shall direct
the executor therein to comply with all of the terms and provisions of this
Agreement.

     10.8  Notices.  Any and all notices given in connection with this Agreement
           -------
shall be deemed adequately given only if in writing and personally delivered
(including overnight delivery by messenger); sent by first class registered or
certified mail, postage prepaid, return receipt requested; or sent by facsimile,
provided a hard copy is mailed on that date to the party for whom such notices
are intended. A written notice shall be deemed to have been given to the
recipient party on the earlier of (i) the date it shall be delivered to the
address required by this Agreement; (ii) the date delivery shall have been
refused at the address required by this Agreement; (iii) with respect to notices
sent by mail, the date as of which the postal service shall have indicated such
notice to be undelivered at the address required by this Agreement, or (iv) with
respect to facsimile, the date on which the facsimile is sent. Any and all
notices referred to in this Agreement, or which any party desires to give to the
other, shall be addressed as follows:
<PAGE>



     Name                     Address

     To the Corporation       The GSI Group, Inc.
                              P.O. Box 20
                              Assumption, IL  62510
                              Attn:  Chief Executive Officer

     To Sloan:                John C. Sloan
                              c/o The GSI Group, Inc.
                              P.O. Box 20
                              Assumption, IL 62510

     To Andrade:              Jorge Andrade
                              c/o The GSI Group, Inc.
                              P.O. Box 20
                              Assumption, IL 62510

     To Buffett:              Howard G. Buffett
                              c/o The GSI Group, Inc.
                              P.O. Box 20
                              Assumption, IL 62510

or to such other address as the person to whom notice is to be given may have
furnished to the other in writing in accordance herewith.  A communication given
by any other means shall be deemed duly given when actually received by the
addressee.

     10.9  Specific Performance.  The Shares cannot be readily purchased or sold
           --------------------
in the open market, and for that reason, among others, the parties will be
irreparably damaged in the event that this Agreement is not specifically
enforced.  Should any dispute arise concerning whether a proposed sale or
disposition of the Shares would violate this Agreement, the parties agree that
an injunction may be issued restraining any sale or disposition pending the
resolution of such controversy.  In the event of any controversy concerning the
right or obligation to purchase or sell any of the Shares, such right or
obligation shall be enforceable in a court of equity by a decree of specific
performance.  Such remedy shall, however, be cumulative and not exclusive, and
shall be in addition to any other remedy which the parties may have at law, in
equity or otherwise.

     10.10  Construction of Terms.  Unless otherwise specifically provided, a
            ---------------------
reference to a particular "Subsection", "Section", or "Article" shall mean the
Subsection, Section or Article in this Agreement.

     10.11  Governing Law.  This Agreement shall be interpreted, governed and
            -------------
construed in all respects in accordance with the internal laws of the State of
Illinois, and any action commenced to enforce any of the provisions hereof shall
be brought either in the Illinois Circuit Court for the Fourth Judicial Circuit
or the United States District Court for the Central District of Illinois,
Springfield Division.

     10.12  Payment of Legal Costs and Expenses.  In the event any action is
            -----------------------------------
commenced to challenge or enforce the terms and provisions hereof, the party who
is successful in such action based upon a final, unappealable court order, shall
be reimbursed by the unsuccessful party for
<PAGE>



his fees, costs, and expenses (including, without limitation, reasonable
attorneys' and accountants' fees, costs, and expenses) incurred in connection
with the legal proceeding.

     10.13  Gender.  Unless the context otherwise requires, any pronouns,
            ------
wherever used herein, shall be deemed to include the corresponding masculine,
feminine, or neuter pronouns and the plural shall include the singular, and vice
versa.

     10.14  Headings.  Article and section headings are included herein solely
            --------
for convenience and shall not be construed to modify or explain any of the
substantive provisions hereof.



     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed and attested by its duly authorized officer, and the Shareholders have
signed their names, all on the day and year first above written.

                              THE GSI GROUP, INC., a Delaware corporation


                              By:  /s/ John C. Sloan
                                   ---------------------------
                              Its:  Chief Executive Officer

                                   /s/ Jorge Andrade
                                   ---------------------------
                                   JORGE ANDRADE

                                   /s/ Howard G. Buffett
                                   ---------------------------
                                   HOWARD G. BUFFETT

                                   /s/ John C. Sloan
                                   ---------------------------
                                   JOHN C. SLOAN