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                                                                   EXHIBIT 10.18

                  FIRST AMENDMENT TO STOCK PURCHASE AGREEMENT
                  -------------------------------------------

     THIS FIRST AMENDMENT TO STOCK PURCHASE AGREEMENT (this "First Amendment")
is made and entered into this 14th day of October, 1996, by and between
FINANCIAL SERVICE CORPORATION, a Georgia corporation with its principal
executive offices in Cobb County, Georgia (the "Company"), and E. JAMES WISNER,
a resident of Fulton County, Georgia ("Wisner").

                              W I T N E S  E T H:

     WHEREAS, on October 2, 1991, the Company and Wisner entered into that
certain Stock Purchase Agreement (the "Stock Purchase Agreement") pursuant to
which the Company and Wisner agreed that, upon Wisner's death, the Company would
purchase certain shares of Common Stock of the Company then owned by Wisner on
terms, and subject to conditions, set forth in said Stock Purchase Agreement;
and

     WHEREAS, the Company and Wisner have each determined that it is in their
respective best interests to amend the Stock Purchase Agreement to, among other
things, (i) provide for a different method of calculating the purchase price to
be paid by the Company for certain shares of Company Common Stock held by Wisner
at his death, (ii) reflect that the Company has obtained additional life
insurance with which to fund a portion of the purchase price and (iii) provide
that life insurance  proceeds in excess of those required to fund a portion of
the purchase price will be paid to the Company and not to Wisner's estate;

     NOW, THEREFORE, FOR AND IN CONSIDERATION of the sum of Ten and No/100
Dollars ($10.00), the premises, the covenants hereinafter set forth and other
good and valuable consideration, the receipt and sufficiency of which hereby are
acknowledged, the parties hereto, intending to be legally bound, do hereby agree
as follows:

     1.   General.     Capitalized terms not otherwise defined herein shall
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          have the respective meanings given to such terms in the Stock Purchase
          Agreement. The Stock Purchase Agreement, as hereby amended, shall
          remain in full force and effect in accordance with its terms as
          amended hereby. From and after the date of this First Amendment,
          references to the Stock Purchase Agreement shall be deemed to be
          references to the Stock Purchase Agreement as amended by this First
          Amendment.

     2.   Definitions. Section 1 of the Stock Purchase Agreement is hereby
          -----------
          amended as follows:

          (a)  The definition of "Book Value" that is set forth in Section 1 of
          the Stock Purchase Agreement is deleted in its entirety and the
          following definition is inserted in lieu thereof:

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               "Book Value" shall mean the book value per share of Common Stock
               of the Company as reflected on the consolidated financial
               statements of the Company prepared as of the last day of the
               month immediately preceding the month in which Wisner dies and
               determined in accordance with generally accepted accounting
               principles consistently applied, which statements shall be
               certified by the Company's principal financial officer (who for
               purposes of this Agreement must be someone other than Wisner) as
               presenting fairly the financial condition of the Company.

          (b)  The definition of "Policy" that is set forth in Section 1 of the
          Stock Purchase Agreement is deleted in its entirety and the following
          definition is inserted in lieu thereof:

               "Policy" shall mean (i) the term life insurance policy (policy
               number 79622023) issued by The Prudential Insurance Company of
               America in the amount of $1,300,000 on the life of Wisner, a copy
               of which is attached as Exhibit I to the First Amendment to Stock
               Purchase Agreement and (ii) the term life insurance policy
               (policy number 2609892) issued by First Colony Life Insurance Co.
               in the amount of $3,500,000 on the life of Wisner, a copy of
               which is attached as Exhibit II to the First Amendment to Stock
               Purchase Agreement.

          (c)  The definition of "Purchase Price" that is set forth in Section 1
          of the Stock Purchase Agreement is deleted in its entirety and the
          following definition is inserted in lieu thereof:

               "Purchase Price" of a share of Wisner Stock shall mean an amount
               equal to the sum of (i) the per share Book Value (as adjusted for
               stock splits, stock dividends, recapitalizations and other
               similar events occurring between the date of the financial
               statements from which Book Value is determined and the initial
               purchase date and (ii) the Purchase Price Adjustment (hereinafter
               defined), if any.

          (d)  Immediately following the definition of "Purchase Price" there is
          hereby added the following definition:

               "Purchase Price Adjustment" shall mean an amount per share of
               Wisner Stock determined as follows.  If no Sale (hereinafter
               defined) occurs prior to the end of the twenty-fourth month
               following the month in which Wisner dies, the amount of the
               Purchase Price Adjustment shall be zero.  If a Sale does occur
               prior to the end of the twenty-fourth month following the month
               in which Wisner dies, the
<PAGE>

               Purchase Price Adjustment shall be equal to (i) the "Adjustment
               Factor" (calculated as set forth below) multiplied by (ii) a
               fraction, the denominator of which is 24 and the numerator of
               which is the number of whole and partial months remaining between
               the month in which the Sale occurs and the end of the twenty-four
               month period; provided, however, that in no event shall the
               numerator be greater than 24. The numerator shall include the
               month in which the Sale occurs.

               For purposes of this definition of Purchase Price Adjustment, the
               Adjustment Factor shall be calculated as follows.  If the fair
               market value of the consideration per share of Company Common
               Stock received by holders thereof in connection with any Sale
               (which fair market value per share shall be calculated for this
               purpose as though the same number of shares of Company Common
               Stock are outstanding on the date of the Sale as were outstanding
               on the date as of which Book Value was calculated) is not greater
               than two (2) times Book Value, the Adjustment Factor shall be
               zero.  If the fair market value of the consideration per share of
               Company Common Stock received by holders thereof in connection
               with any Sale (which fair market value per share shall be
               calculated for this purpose as though the same number of shares
               of Company Common Stock are outstanding on the date of the Sale
               as were outstanding on the date as of which Book Value was
               calculated) is greater than two (2) times Book Value, the
               Adjustment Factor shall equal the difference between two (2)
               times Book Value and the fair market value of the consideration
               per share of Company Common Stock received by holders thereof in
               connection with the Sale (which fair market value per share shall
               be calculated for this purpose as though the same number of
               shares of Company Common Stock are outstanding on the date of the
               Sale as were outstanding on the date as of which Book Value was
               calculated).

     (e)  Immediately following the definition of "Purchase Price Adjustment"
there is hereby added the following definition:

               "Sale" shall mean the consummation, following the date of
               Wisner's death, of any of the following: (i) a sale of
               substantially all of the assets of the Company, or of any
               subsidiary or subsidiaries of the Company, that results in
               consideration being distributed to holders of Company Common
               Stock; (ii) a sale of then previously issued and outstanding
               shares of the Company, or of any subsidiary or subsidiaries of
               the Company, which sale (a) results in a change in beneficial
               ownership of 50% or more of the issued and outstanding Common
               Stock to the Company, or 50% or
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               more of the issued and outstanding voting stock of such
               subsidiary or subsidiaries and (b) results in consideration being
               distributed to holders of Company Common Stock; or (iii) a merger
               or share exchange involving the Company, or any subsidiary or
               subsidiaries of the Company, which merger or share exchange
               results in consideration being distributed to holders of Company
               Common Stock.

     (f)  The definition of "Wisner Stock" that is set forth in Section 1 of the
          Stock Purchase Agreement is deleted in its entirety and the following
          definition is inserted in lieu thereof:

               "Wisner Stock" shall mean (i) the 248,098 shares of Company
               Common Stock beneficially owned by Wisner on the date hereof and
               (ii) any securities issued or issuable with respect to such
               shares of Common Stock by way of stock dividend or stock split or
               in connection with a combination of shares, recapitalization,
               merger, consolidation, or other reorganization or otherwise, but
               the shares referred to in the foregoing clauses (i) and (ii)
               shall be "Wisner Stock" only so long as they are beneficially
               owned by Wisner or, after Wisner's death, by Wisner's estate.
               Other than as provided above, "Wisner Stock" shall not include
               any shares of Common Stock acquired by Wisner after the date
               hereof (including any shares beneficially owned on the date
               hereof, transferred to a third party (unless Wisner retains
               beneficial ownership), and subsequently reacquired by Wisner).
               Wisner shall be deemed to "beneficially own" any shares of Common
               Stock which he owns of record, which are held in trust for his
               benefit, or from which he otherwise derives a direct pecuniary
               benefit.  Wisner also shall be deemed to "beneficially own" any
               shares of Common Stock held in trust for the benefit of his
               spouse or children,  or other relatives that are his dependents,
               or any shares of Common Stock owned beneficially and of record by
               such persons, in either case to the extent that such shares were
               acquired from Wisner, whether by gift or purchase.  "Wisner
               Stock" shall not include any options, warrants, or other
               contractual rights to acquire shares of Common Stock.

     3.   Payment.  Section 2(b) of the Stock Purchase Agreement is hereby
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amended by deleting said Section 2(b) in its entirety and inserting, in lieu
thereof, the following:

          (b)  Payment.
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               (i) Purchase Price Excluding Purchase Price Adjustment.   The
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               Company shall pay the aggregate Purchase Price (excluding the
               Purchase Price Adjustment) by wire transfer of immediately

<PAGE>

               available funds to an account designated by the Representative in
               writing at least two days prior to the date of such payment,
               except that:


                    (a) If (I) Wisner dies on or before March 2, 2007 (Wisner's
                    65th birthday), or (II) Wisner dies after March 2, 2007, but
                    the Company has continued to maintain the Policy after such
                    date, then to the extent that the aggregate Purchase Price
                    (excluding the Purchase Price Adjustment) exceeds
                    $4,800,000, the Company, at its option, may issue and
                    deliver to or at the direction of the Representative a
                    promissory note substantially in the form attached as
                    Exhibit A to this Stock Purchase Agreement (the "Note") in
                    payment of the amount of the aggregate Purchase Price
                    (excluding the Purchase Price Adjustment) in excess of
                    $4,800,000; and

                    (b) If Wisner dies after March 2, 2007, and the Company has
                    not continued to maintain the Policy, then the Company shall
                    pay at least one-fourth of the aggregate Purchase Price
                    (excluding the Purchase Price Adjustment) in immediately
                    available funds but, at its option, may issue and deliver to
                    or at the direction of the Representative the Note in
                    payment of the remainder of the aggregate Purchase Price
                    (excluding the Purchase Price Adjustment).

                    If the Note is delivered under Section 2(b)(i)(a), it shall
                    have a term of 60 months, and if the Note is delivered under
                    Section 2(b)(i)(b), it shall have a term of 120 months.

               (ii) Purchase Price Adjustment. The aggregate amount of the
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               Purchase Price Adjustment shall be paid immediately following the
               consummation of the Sale that is the cause of the Purchase Price
               Adjustment.  No less than ten (10) days prior to the consummation
               of such Sale, the Company shall notify the Representative in
               writing of the date on which the Sale will be consummated.
               Representative shall then notify the Company in writing, at least
               two days prior to the proposed consummation date, of the account
               into which the Purchase Price Adjustment is to be deposited.  The
               Company shall cause the Purchase Price Adjustment to be wired, in
               immediately available funds, to the account designated by the
               Representative.
<PAGE>

     4.   Closing.  Section 2(c) of the Stock Purchase Agreement is hereby
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amended by deleting the last sentence of said Section in its entirety and
inserting, in lieu thereof, the following:

               Except as provided otherwise in Section 3 below, on the date
               fixed for the purchase, the Representative shall surrender the
               certificates representing the Wisner Stock, free and clear of all
               liens and encumbrances and properly endorsed for transfer, at the
               principal office of the Company, against payment of the aggregate
               Purchase Price (excluding the Purchase Price Adjustment) for the
               Wisner Stock.

     5.   Limitation of Purchase Obligation.  Section 3(a) of the Stock
          ---------------------------------
Purchase Agreement is hereby amended by deleting the reference to "Section 2(b)"
that is contained in said Section and inserting, in lieu thereof, a reference to
"Section 2(b)(i)."

     6.   Security Interest.   Section 4 of the Stock Purchase Agreement is
          -----------------
hereby amended by deleting said Section 4 in its entirety and inserting, in lieu
thereof, the following:

          SECTION 4.     Security Interest.

          (a)  Grant of Security Interest.  As security for the payment of the
          Purchase Price (excluding the Purchase Price Adjustment), the Company
          hereby assigns, transfers and pledges to Wisner a continuing first
          priority security interest in all of the Company's right, title and
          interest in the Policy and any proceeds thereof (the "Collateral") and
          hereby delivers the Policy and a collateral assignment thereof (the
          "Assignment") to Wisner, receipt of which is hereby acknowledged by
          Wisner.

          (b)  Representations and Warranties.  The Company represents and
          warrants to Wisner that except for the security interest granted
          hereunder and any interests or liens that may have been created before
          Wisner transferred the Policy to the Company, the Company is the legal
          and equitable owner of the Collateral and holds the Collateral free
          and clear of any liens, and the Company will not make any sale,
          assignment, pledge, mortgage, or transfer of the Collateral except
          pursuant to this Agreement.  The Company covenants that it shall pay
          the premiums and otherwise maintain the Policy as provided in Section
          5.

          (c)  Further Assistance.  The Company agrees, at its expense, promptly
          to execute, acknowledge, deliver and cause to be duly filed all such
          further instruments and documents and take all such actions as Wisner
          may from time to time reasonably request to better assure and preserve
          the security interest and the rights and remedies created hereby,
          including the payment of any fees and taxes required in connection
          with the execution
<PAGE>

          and delivery of this Agreement, the granting of the security interest
          created hereby, and the filing of any financing statements or other
          documents in connection herewith. Without limiting the foregoing,
          Wisner is hereby authorized to file one or more financing statements,
          continuation statements, or other documents for the purpose of
          perfecting, confirming, continuing, enforcing or protecting the
          security interest granted by the Company hereunder, without the
          signature of the Company, naming the Company as debtor and Wisner as
          secured party.

          (d)  Enforcement.   If the Company fails to pay the Purchase Price
          (excluding the Purchase Price Adjustment) in accordance with the terms
          of this Agreement, the Representative may, on Wisner's behalf, proceed
          to protect and enforce the rights vested in Wisner by this Agreement,
          including the right to cause the proceeds of the Policy (up to the
          amount of the Purchase Price excluding the Purchase Price Adjustment)
          to be paid directly to Wisner's estate or to another seller of Wisner
          Stock hereunder, and to enforce Wisner's rights hereunder to such
          proceeds and all other rights hereunder by such appropriate judicial
          proceedings as it shall deem most effective to protect and enforce any
          of such rights, either at law or in equity or in bankruptcy or
          otherwise, and it may exercise any other or additional rights or
          remedies granted to a secured party under applicable law.

          (e)  Termination of Security Interest.  The security interest granted
          by the Company hereunder shall terminate on the earlier to occur of:
          (i) the termination of this Agreement or (ii) the transfer of the
          Policy to Wisner or at the direction of Wisner pursuant to Section
          5(d).

     7.   Payment of Premiums; Maintenance of Policy and Payment of Excess
          ----------------------------------------------------------------
Proceeds.  Section 5 of the Stock Purchase Agreement is hereby amended by
--------
deleting said Section 5 in its entirety and inserting, in lieu thereof, the
following:

          SECTION 5 Payment of Premiums; Maintenance of Policy and Payment of
          Excess Proceeds.

          (a)  Company's Payment Obligation.  For so long as the security
          interest described in Section 4 is in effect, the Company shall pay
          all premiums and other expenses on the Policy as they become due
          through March 2, 2007 (the date of Wisner's 65th birthday).  The
          Company may, but is not required to, continue to pay such premiums and
          expenses after such date.

          (b)  Wisner's Right to Cure Nonpayment.  So long as the Company is
          obligated to pay the premiums and expenses of the Policy, if at any
          time a premium or expense is not paid within twenty days after its due
          date, Wisner shall be entitled to pay such premium or expense as agent
          of the Company, and the Company shall reimburse him promptly
<PAGE>

          (in cash or by delivery of a demand promissory note of the Company
          substantially in the form attached hereto as Exhibit B) for any such
          payment. The Company shall notify Wisner of any nonpayment of any such
          premium or expense within twenty days after its due date and shall
          authorize and direct The Prudential Insurance Company of America and
          First Colony Life Insurance Co. to give Wisner, upon his written
          request, any information about the status of the Policy.

          (c)  Wisner's Obligation to Cooperate.  Wisner agrees to take any
          physical examinations and sign any applications as shall be necessary
          from time to time to maintain the Policy or to enable the Company to
          obtain any additional insurance.

          (d)  Transfer of Policy upon Termination of Company's Payment
          Obligation.  When the Company is no longer obligated, and has not
          elected, to maintain the Policy as provided in Section 5(a), the
          Company shall transfer the Policy to or at the direction of Wisner and
          shall change or assist in the changing of the beneficiary under the
          Policy at Wisner's direction.

          (e)  Payment of Excess Proceeds.  If, pursuant to the terms of this
          Agreement, the Policy continues to be maintained by the Company at the
          time of Wisner's death, the Company shall be entitled to any and all
          proceeds of the Policy which exceed the aggregate amount of the
          Purchase Price (excluding the Purchase Price Adjustment).


     8.   Termination.   Section 9 of the Stock Purchase Agreement is
          -----------
hereby amended by deleting said Section 9 in its entirety and inserting, in lieu
thereof, the following:


          SECTION 9. Termination of this Agreement. This Agreement shall
          terminate upon the first to occur of the following:

          (a)  The mutual written agreement of the Company and Wisner to
          terminate this Agreement;

          (b)  The merger of the Company with another corporation or entity, or
          the sale of all or substantially all of the assets of the Company to
          another corporation or entity, in which a majority of the voting
          equity interest of the surviving or successor corporation or entity is
          not owned by the persons who immediately before the transaction were
          shareholders of the Company; provided, however, that notwithstanding
          anything in this Agreement to the contrary, the obligation of the
          Company to pay, or cause to be paid, the Purchase Price Adjustment
          shall survive any termination of this Agreement pursuant to this
          Section 9(b); or
<PAGE>

          (c)  The date of which either of the following exists: (i) Wisner
          shall be alive and shall not beneficially own any shares of Wisner
          Stock or (ii) Wisner shall have died and the full amount of the
          Purchase Price (including the Purchase Price Adjustment) shall been
          paid by the Company.

          Upon the termination of this Agreement, the security interest granted
          hereby shall be terminated and the Company shall promptly assign the
          Policy to Wisner, if he is then living.  Once terminated, neither this
          Agreement nor the security interest created hereby shall be reinstated
          by any subsequent acquisition of shares of Common Stock by Wisner.

     9.   Governing Law. This First Amendment shall be governed by, and
          -------------
construed in accordance with, the internal laws of the State of Georgia
applicable to agreements made and to be performed entirely within such state.

     10.  Counterparts. This First Amendment may be executed simultaneously in
          ------------
one or more counterparts, each of which shall be deemed an original, but all of
which together shall constitute one and the same agreement.

     IN WITNESS WHEREOF, the parties hereto have affixed their respective hands
and seals, or have caused this First Amendment to be executed by their duly
authorized officers, this 14th day of October, 1996.

                                    FINANCIAL SERVICE CORPORATION


                                    By: /s/Thomas W. Hutchins
                                        ---------------------------
                                        Title: Senior Vice President



                                    /s/E. James Wisner       (SEAL)
                                    -------------------------
                                    E. James Wisner
<PAGE>

                                  "Exhibits"


Exhibit I.

Prudential Insurance Company Of America;
Policy No. #79622023
           ---------
Policy Amount:  $1,300,000


Exhibit II.

First Colony Life Insurance Company;
Policy No. #2609892
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Policy Amount:  $3,500,000