<PAGE>
                                                                  EXHIBIT 10.1.6



                                                     August 18, 2005


Asia Automotive Acquisition Corporation
401 South Old Woodward, Suite 450
Birmingham, Michigan 48009

Rodman & Renshaw, LLC
1270 Avenue of the Americas, 16th Floor
New York, NY 10020

                  Re:      Initial Public Offering

Gentlemen:

                  The undersigned director of Asia Automotive Acquisition
Corporation ("Company"), in consideration of Rodman & Renshaw, LLC ("Rodman &
Renshaw") entering into a letter of intent ("Letter of Intent") to underwrite an
initial public offering of the securities of the Company ("IPO") and embarking
on the IPO process, hereby agrees as follows (certain capitalized terms used
herein are defined in paragraph 12 hereof):

                  1. If the Company solicits approval of its stockholders of a
Business Combination, the undersigned will vote all Insider Shares owned by it
in accordance with the majority of the votes cast by the holders of the IPO
Shares.

                  2. In the event that the Company fails to consummate a
Business Combination within 18 months from the effective date ("Effective Date")
of the registration statement relating to the IPO (or 24 months under the
circumstances described in the prospectus relating to the IPO), the undersigned
will vote all Insider Shares owned by it in favor of the Company's decision to
liquidate. The undersigned hereby waives any and all right, title, interest or
claim of any kind in or to any distribution of the Trust Fund (as defined in the
Letter of Intent) and any remaining net assets of the Company as a result of
such liquidation with respect to its Insider Shares ("Claim") and hereby waives
any Claim the undersigned may have in the future as a result of, or arising out
of, any contracts or agreements with the Company and will not seek recourse
against the Trust Fund for any reason whatsoever. In the event of the
liquidation of the Trust Fund, the undersigned agrees to indemnify and hold
harmless the Company, pro rata with the other officers and directors of the
Company, based on the number of Insider Shares held by each such individual,
against any and all loss, liability, claims, damage and expense whatsoever
(including, but not limited to, any and all legal


                                      -1-

<PAGE>

or other expenses reasonably incurred in investigating, preparing or defending
against any litigation, whether pending or threatened, or any claim whatsoever)
which the Company may become subject as a result of any claim by any vendor or
other person who is owed money by the Company for services rendered or products
sold or contracted for, or by any target business, but only to the extent
necessary to ensure that such loss, liability, claim, damage or expense does not
reduce the amount in the Trust Fund. The foregoing sentence is not for the
benefit of any third party creditors of the Company.

                  3. In order to minimize potential conflicts of interest which
may arise from multiple affiliations, the undersigned agrees to present to the
Company for its consideration, prior to presentation to any other person or
entity, any suitable opportunity to acquire an operating business, until the
earlier of the consummation by the Company of a Business Combination, the
liquidation of the Company or until such time as the undersigned ceases to be an
officer or director of the Company, subject to any pre-existing fiduciary and
contractual obligations the undersigned might have.

                  4. The undersigned acknowledges and agrees that the Company
will not consummate any Business Combination which involves a company which is
affiliated with any of the Insiders unless the Company obtains an opinion from
an independent investment banking firm reasonably acceptable to Rodman & Renshaw
that the business combination is fair to the Company's stockholders from a
financial perspective.

            5. Neither the undersigned, any member of the family of the
undersigned, nor any affiliate ("Affiliate") of the undersigned will be entitled
to receive and will not accept any compensation for services rendered to the
Company prior to the consummation of the Business Combination. Notwithstanding
the foregoing to the contrary, the undersigned shall be entitled to
reimbursement from the Company for its out-of-pocket expenses incurred in
connection with seeking and consummating a Business Combination and commencing
on the Effective Date, Asia Development Capital LLC ("Related Party"), shall be
allowed to charge the Company $7,500 per month, representing an allocable share
of Related Party's overhead, to compensate it for the Company's use of Related
Party's offices, utilities and personnel.

                  6. Neither the undersigned, any member of the family of the
undersigned, nor any Affiliate of the undersigned will be entitled to receive or
accept a


                                      -2-
<PAGE>

finder's fee or any other compensation in the event the undersigned, any member
of the family of the undersigned or any Affiliate of the undersigned originates
a Business Combination.

                  7. The undersigned will escrow its Insider Shares for the
three year period commencing on the Effective Date subject to the terms of a
Stock Escrow Agreement which the Company will enter into with the undersigned
and an escrow agent acceptable to the Company.

                  8. The undersigned agrees to be a member of the Company's
board of directors until the earlier of the consummation by the Company of a
Business Combination or the liquidation of the Company. The undersigned's
biographical information furnished to the Company and Rodman & Renshaw and
attached hereto as Exhibit A is true and accurate in all respects, does not omit
any material information with respect to the undersigned's background and
contains all of the information required to be disclosed pursuant to Item 401 of
Regulation S-K, promulgated under the Securities Act of 1933. The undersigned's
Questionnaire furnished to the Company and Rodman & Renshaw and annexed as
Exhibit B hereto is true and accurate in all respects. The undersigned
represents and warrants that:

         (a) he is not subject to or a respondent in any legal action for, any
injunction, cease-and-desist order or order or stipulation to desist or refrain
from any act or practice relating to the offering of securities in any
jurisdiction;

         (b) he has never been convicted of or pleaded guilty to any crime (i)
involving any fraud or (ii) relating to any financial transaction or handling of
funds of another person, or (iii) pertaining to any dealings in any securities
and he is not currently a defendant in any such criminal proceeding; and

         (c) he has never been suspended or expelled from membership in any
securities or commodities exchange or association or had a securities or
commodities license or registration denied, suspended or revoked.

                  9. The undersigned has full right and power, without violating
any agreement by which he is bound, to enter into this letter agreement and to
serve as a member of the Company's board of directors.

                  10. The undersigned authorizes any employer, financial
institution, or consumer credit reporting agency to release to Rodman & Renshaw
and its legal representatives or agents (including any investigative search firm
retained by Rodman & Renshaw) any information they may have about the
undersigned's background and finances ("Information"). Neither Rodman & Renshaw
nor its agents shall be violating the undersigned's right of privacy in any
manner in requesting and obtaining the Information and the undersigned hereby
releases them from liability for any damage whatsoever in that connection.


                                      -3-
<PAGE>

                  11. This letter agreement shall be governed by and construed
and enforced in accordance with the laws of the State of New York, without
giving effect to conflicts of law principles that would result in the
application of the substantive laws of another jurisdiction. The undersigned
hereby (i) agrees that any action, proceeding or claim against him arising out
of or relating in any way to this letter agreement (a "Proceeding") shall be
brought and enforced in the courts of the State of New York of the United States
of America for the Southern District of New York, and irrevocably submits to
such jurisdiction, which jurisdiction shall be exclusive, (ii) waives any
objection to such exclusive jurisdiction and that such courts represent an
inconvenient forum and (iii) irrevocably agrees to appoint Kramer Levin Naftalis
& Frankel LLP as agent for the service of process in the State of New York to
receive, for the undersigned and on his behalf, service of process in any
Proceeding. If for any reason such agent is unable to act as such, the
undersigned will promptly notify the Company and Rodman & Renshaw and appoint a
substitute agent acceptable to each of the Company and Rodman & Renshaw within
30 days and nothing in this letter will affect the right of either party to
serve process in any other manner permitted by law.

                  12. As used herein, (i) a "Business Combination" shall mean an
acquisition by merger, capital stock exchange, asset or stock acquisition,
reorganization or otherwise, of an operating business whose primary operations
are in India and selected by the Company; (ii) "Insiders" shall mean all
officers, directors and stockholders of the Company immediately prior to the
IPO; (iii) "Insider Shares" shall mean all of the shares of Common Stock of the
Company owned by an Insider prior to the IPO; and (iv) "IPO Shares" shall mean
the shares of Common Stock issued in the Company's IPO.

                                        Donald L. Runkle
                                        -----------------------
                                        Print Name of Insider


                                    By: /s/ Donald L. Runkle
                                        -----------------------
                                        Name: Donald L. Runkle
                                        Title:   Director


                                      -4-