Document:

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                                                                   EXHIBIT 10.30

                                 December 16, 1999

Mr. Joseph McCarthy
Vice President and General Counsel
Lear Corporation
21557 Telegraph Road
Southfield, Michigan 48034

Dear Joe:

     This letter sets forth the terms and conditions under which Donnelly will
purchase all the outstanding stock of Eurotrim.  Capitalized terms in this
letter have the meanings set forth in the Redemption and Purchase Agreement (the
"Agreement") and the Eurotrim Agreement.

1.   Donnelly will purchase the Volvo console business by purchasing all of the
     outstanding Eurotrim stock from Lear Donnelly, recognizing that Eurotrim
     and Donnelly will be responsible for all obligations of Eurotrim under the
     Agreement, including the cost to close down the City West Facility.
     Donnelly will pay a net purchase price for all of the outstanding stock of
     Eurotrim of $2,375,000.  The payment will be made by wired funds at
     closing.

2.   The purchase price paid for the Eurotrim stock is inclusive of all items
     paid by each party, except as specifically provided herein.  Accordingly,
     there will be no other payments or repayments of prepaid employee costs,
     shutdown costs, inventory build-up or other costs incurred by either party.

3.   Lear Donnelly will assume all indebtedness for borrowed money of Eurotrim
     at or prior to closing and Lear and Lear Donnelly hereby agree to indemnify
     and hold harmless Donnelly and Eurotrim from any loss, cost or liability
     arising from such indebtedness.

4.   At the Closing, Lear Donnelly will deliver to Donnelly or a subsidiary of
     Donnelly

     a.   a duly executed stock power transferring all outstanding Eurotrim
          stock;

     b.   resignations of the directors and officers of Eurotrim; and

     c.   a statement of representations and warranties in the form attached as
          Exhibit A.

5.   The closing will occur on or before December 17, 1999.
<PAGE>

6.   Lear and Lear Donnelly will cooperate with Donnelly and Eurotrim to provide
     all information required to complete and file all tax returns and other
     reports for Eurotrim with respect to the operation of Eurotrim between
     November 1, 1997, and the date of closing.

7.   The Company's agreement to indemnify Donnelly for liabilities Donnelly may
     incur as surety under the Naas Road Lease, as set forth in the Side Letter
     Concerning Eurotrim Lease Indemnity, dated November 1, 1997, is canceled
     and of no further force and effect.

8.   Donnelly's obligation under the Donnelly Amended Non-Competition and Non-
     Solicitation Agreement will be modified to permit Donnelly to manufacture
     and sell overhead console (as defined in the Eurotrim Agreement) and any
     modification or replacement thereof (the "Consoles") to Volvo or any Volvo
     supplier.

9.   Lear and its affiliates will agree not to seek or accept from Volvo or JCI
     Becker any order for the Consoles and will not encourage Volvo to award
     such business to any other party or interfere in any way with Donnelly's
     agreement to manufacture the Consoles.

10.  The Agreement is amended by deleting Subsection 1.3(b) and Section 9.15 and
     by amending Section 9.16 to provide that Lear shall retain the entire
     $6,250,000 withheld from payment to Donnelly.

11.  Schedule 4.9(b) of the Agreement is hereby amended to provide that
     Donnelly's Sales Price to Lear Donnelly as a percentage of Customer Price
     is 58.9% for the LH Platform Door Lamp.

12.  This Letter Agreement and the document to be delivered in the form of
     Exhibit A are deemed to be an amendment to the Agreement and subject to its
     terms and conditions.

     If the terms of this letter are acceptable, please sign a copy in the space
provided below and return it to me.
                                        Very truly yours,

                                        DONNELLY CORPORATION

                                        By /s/ Scott Reed, Sr.
                                           ------------------------------------
                                           Scott Reed, Sr.  Vice President and
                                           Chief Financial Officer

ACCEPTED:

LEAR CORPORATION

By /s/ Joseph McCarthy
   -----------------------------------
   Joseph McCarthy
   Vice President and General Counsel

Dated:   December 16, 1999
<PAGE>

                                   EXHIBIT A

                REPRESENTATIONS, WARRANTIES AND INDEMNIFICATION

1.   REPRESENTATIONS AND WARRANTIES.  Except as set forth in the Lear Disclosure
     Schedule amended as attached hereto, Lear and the Company represent and
     warrant to Donnelly that the following representation and warranties are
     true and correct on the date hereof.

     a.   Title.  The Company has, and upon consummation of the closing under
          this letter agreement Donnelly or its assignee will acquire, good,
          valid and marketable right, title and interest to all of the issued
          and outstanding stock of Eurotrim.

     b.   Transfers by Eurotrim.  Since September 15, 1999, Eurotrim has made no
          payment to or made any commitment to make any payment to Lear, the
          Company or any of their affiliates and has made no payments with
          respect to indebtedness for borrowed money.

     c.   Debt.  Eurotrim has no indebtedness for borrowed money.

     d.   Eurotrim Lease.  The Company and Lear have conducted discussions with
          the landlord of Eurotrim's plant regarding termination of the lease or
          anticipated severance payments and have informed Donnelly of the
          substance of those discussions.

     e.   Disclosure.  To the knowledge of Lear and the Company, Eurotrim has
          been operated only in the ordinary course of business since September
          15, 1999, and there is no material fact that has not been disclosed to
          Donnelly that has or could have a material adverse effect on Eurotrim.

     f.   Eurotrim Facility.  With regard to Eurotrim's facility:

          (1)  Status of Equipment. To the knowledge of Lear and the Company,
               the equipment, machinery and other assets of Eurotrim are in good
               operating condition and repair (normal wear and tear excepted).

          (2)  Environmental Matters.

               A.   To Lear's and the Company's knowledge, the Eurotrim holds
                    all Environmental Permits necessary to conduct its business
                    as presently conducted. Eurotrim has received no notice from
                    any governmental authority with respect to the revocation or
                    amendment of any Environmental Permit;

               B.   To Lear's and the Company's knowledge, there is no civil,
                    criminal or administrative action, suit, summons, citation,
                    complaint, claim,
<PAGE>

                    notice of violation, demand, judgment, order, lien,
                    proceeding or hearing or any study, inquiry, proceeding or
                    investigation relating to the Business, threatened against
                    Eurotrim based on, stemming form or related to any
                    Environmental Permit or any environmental Law or any
                    Hazardous Substance.

               C.   To Lear's and the Company's knowledge, Eurotrim's facility
                    is free of any Hazardous Substances (except those authorized
                    pursuant to and in accordance with Environmental Permits
                    held by Eurotrim) and free of all contamination, including
                    but not limited to groundwater contamination, arising from,
                    relating to, or resulting from any such Hazardous
                    Substances.

               D.   To Lear's and the Company's knowledge, Eurotrim has not
                    received any written notice or other communication that
                    Eurotrim is or may be a potentially responsible person or
                    otherwise liable in connection with any waste disposal site
                    allegedly containing any Hazardous substances, or other
                    location used for the treatment, storage or disposal of any
                    Hazardous Substances manufactured, generated or used at, or
                    in connection with, or disposed of or transported from, the
                    Eurotrim business.

2.   INDEMNIFICATION.  The indemnity obligations under Section 8(b)(l) of the
     Agreement shall be applicable to the representations and warranties
     contained herein.

                                        LEAR CORPORATION

Dec. ___, 1999.
                                            By
                                              --------------------------------

                                        Its
                                           -----------------------------

                                        LEAR DONNELLY OVERHEAD SYSTEMS LLC

Dec. ___, 1999.
                                            By
                                              --------------------------------

                                        Its
                                           -----------------------------<PAGE>

                                                                   EXHIBIT 10.31

                          BANK ONE, MICHIGAN, as Agent
                               611 Woodward Avenue
                             Detroit, Michigan 48226

                                January 15, 2000

Donnelly Corporation
Donnelly Hohe GmbH & Co. KG
Donnelly Euroglas Systems SARL
49 West Third Street
Holland, Michigan  49423

        Re:   Multicurrency Revolving Credit Loan Agreement dated as of
              September 16, 1997, as amended (the "Loan Agreement") by
              and among Donnelly Corporation (the "Company"), Donnelly
              Hohe GmbH & Co. KG, the Borrowing Subsidiaries party
              thereto (collectively with the Company, the "Borrowers"),
              the Banks named therein (collectively, the "Banks" and
              individually, a "Bank") and Bank One, Michigan, as agent
              for the Banks, successor Agent to The First National Bank
              of Chicago (in such capacity, the "Agent")

Ladies and Gentlemen:

         The Company has requested that certain outstanding letters of credit
issued by Dresdner Bank AG ("Dresdner") and described on Schedule 1.1 attached
hereto (the "Dresdner LCs") be deemed to be "Facility Letters of Credit" under
the Loan Agreement and be subject to the terms and conditions, including
pricing, of the Loan Agreement. Each of the Banks hereby consents to such
request provided that the Loan Agreement is modified as described herein.

         The Company and each of the Banks hereby agrees that the Loan Agreement
shall be amended as follows:

         (a) The definition of "Issuer" in Section 1.1 of the Loan Agreement
shall be deleted and the following shall be inserted in place thereof:
<PAGE>

         "Issuer" means Bank One and, with respect to the Facility Letters of
         Credit identified on Schedule 1.1, Dresdner Bank AG.

         (b) Schedule 1.1 shall be added to the Loan Agreement in the form
attached hereto as Schedule 1.1.

         In connection with such amendments, each of the undersigned
acknowledges and agrees that, as of and after the date hereof, the Dresdner LCs
shall be deemed to be "Facility Letters of Credit" under the Loan Agreement and
shall be subject to all of the terms and conditions of the Loan Agreement
including without limitation, the terms regarding fees set forth in Section
2.21.6 of the Loan Agreement, which fees shall be paid by the Borrower to the
Agent in accordance with Section 2.21.6 of the Loan Agreement.

         In addition, Dresdner hereby: (a) accepts all of the rights and
responsibilities of an "Issuer" under the Loan Agreement with respect to the
Dresdner LCs, (b) agrees that any collateral or any other support provided to or
for the benefit of the Banks, for the pro-rata of the Banks, and (c) agrees that
any request for any extension of any Dresdner LC shall be forwarded immediately
to the Agent and any such request shall be subject to the satisfaction of the
conditions set forth in Section 2.21.1 of the Loan Agreement; provided, however,
that consent of the Banks shall not be required for any extension of the
Dresdner LCs so long as such conditions set forth in Section 2.21.1 of the Loan
Agreement are satisfied. To the extent Dresdner is acting as collateral agent
under clause (b) above, Dresdner shall have all of the rights, responsibilities,
indemnifications, waivers and be otherwise subject to the standards and terms
applicable to the "Agent" under Articles X and XI of the Loan Agreement.

         The agreement of the Banks set forth herein shall not become binding on
the Banks until a duly authorized officer of the Borrowers and the Required
Banks shall have executed the counterpart of this letter and delivered such
counterpart to the Agent. Except as specifically modified above, the Loan
Agreement and the other Loan Documents shall remain in full force and effect and
are hereby ratified and confirmed. The terms used but not defined herein shall
have their respective meanings ascribed thereto in the Loan Agreement. This
letter may be executed in any number of counterparts, and telecopied signatures
shall be valid and enforceable.

                                          Very truly yours,

                                          BANK ONE, MICHIGAN, Individually as a
                                          Bank and as Agent

                                          By: /s/ Ed W. Balle
                                             -----------------------------------
                                              Its: Managing Director
                                                  ------------------------------
<PAGE>

                                      DEUTSCHE GENOSSENSHAFT BANK,
                                      CAYMAN ISLAND BRANCH

                                      By: /s/ W. Casey
                                          --------------------------------------
                                              W. Casey
                                              Its: Vice President

                                      DRESDNER BANK AG, NEW YORK AND
                                      GRAND CAYMAN BRANCHES, Individually
                                      And as Documentation Agent

                                      By: /s/ John W. Sweeney
                                          --------------------------------------
                                              John W. Sweeney
                                              Its:  Vice President

                                      And by: /s/ Beverly G. Cason
                                          --------------------------------------
                                                  Beverly W. Cason
                                                  Its:  Vice President

                                      SOCIETE GENERALE, CHICAGO BRANCH

                                      By: /s/ Editha Paras
                                          --------------------------------------
                                              Editha Paras
                                              Its: Vice President

                                      COMERICA BANK

                                      By: /s/ Lana L Anderson
                                          --------------------------------------
                                              Lana L. Anderson
                                              Its:  Vice President

                                      THE NORTHERN TRUST COMPANY

                                      By: /s/ Brian D. Beitz
                                          --------------------------------------
                                              Brian D. Beitz
                                              Its:  Vice President

                                      BANK OF AMERICA, N.A.

                                      By: /s/ illegible
                                          --------------------------------------
                                              Its: Principal

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