AMENDMENT to CERTAIN PROGRAM DOCUMENTS in relation to the VON KARMAN FUNDING LLC SECURED LIQUIDITY NOTES PROGRAM 2003

Exhibit 10.16

AMENDMENT

to

CERTAIN PROGRAM DOCUMENTS

in relation to the

VON KARMAN FUNDING LLC SECURED LIQUIDITY NOTES PROGRAM 2003

THIS AMENDMENT, dated as of September 30, 2004 (this “Amendment”), is made by and among Von Karman Funding LLC (the “Issuer”), New Century Mortgage Corporation (as Seller and as Servicer under the Mortgage Loan Purchase and Servicing Agreement (as described below), the “Seller,” or the “Servicer,” as the case may be), Citibank, N.A. (the “Swap Counterparty”), and Deutsche Bank Trust Company Americas (the “Collateral Agent”).

WHEREAS, the Issuer, the Seller and the Servicer have heretofore entered into that certain Mortgage Loan Purchase and Servicing Agreement, dated as of September 3, 2003 (the “Mortgage Loan Purchase and Servicing Agreement”) in connection with the issuance of certain Secured Liquidity Notes;

WHEREAS, the Issuer and the Collateral Agent have heretofore entered into that certain Security Agreement, dated as of September 3, 2003 (the “Security Agreement”) under which certain Secured Liquidity Notes have been issued, and subject to certain conditions, may in the future be issued;

WHEREAS, the ultimate parent of the Issuer, the Seller and the Servicer as of September 3, 2003, was New Century Financial Corporation, a company incorporated and existing under the laws of the State of Delaware;

WHEREAS, New Century Financial Corporation, pursuant to a proxy statement/prospectus (the “Proxy Statement/Prospectus”) dated as of August 13, 2004, is seeking approval of its stockholders, inter alia, to convert from its current status as a C corporation into a real estate investment trust (a “REIT”) for U.S. federal income tax purposes, in the manner and subject to the conditions described in such Proxy Statement/Prospectus;

WHEREAS, without limitation of and subject to the disclosures made in the Proxy Statement/Prospectus, as part of the conversion of New Century Financial Corporation into a REIT, a new company known as New Century REIT, Inc. (“New Century REIT”) has been incorporated and is existing under the laws of the State of Maryland, and upon successful completion of the transactions described in the Proxy Statement/Prospectus, inter alia, first, New Century REIT will become the ultimate parent of the Issuer, the Seller and the Servicer, second, New Century REIT will change its name to “New Century Financial Corporation,” and third, New Century Financial Corporation will change its name to “New Century TRS Holdings, Inc.”;

WHEREAS, the Mortgage Loan Purchase and Servicing Agreement and the Security Agreement make various references to New Century Financial Corporation, but do not define such corporation further other than by its name;

WHEREAS, it is the desire and intent of all the parties to the Mortgage Loan Purchase and Servicing Agreement and the Security Agreement, together with the Swap Counterparty, that references in the Mortgage Loan Purchase and Servicing Agreement to “New Century Financial Corporation” be references to the ultimate parent of the Issuer, the Seller and the Servicer, and that following successful completion of the transactions described in the Proxy Statement/Prospectus, such references become references to the entity formerly known as New Century REIT, Inc., and no longer be references to the entity then known as New Century TRS Holdings, Inc.;

WHEREAS, although the precise references in the Mortgage Loan Purchase and Servicing Agreement and the Security Agreement to “New Century Financial Corporation” will not need to be changed to achieve the desires and intents described in the preceding paragraph, the parties hereto nevertheless wish to enter into this Amendment to the Mortgage Loan Purchase and Servicing Agreement and the Security Agreement in order to clarify the substantive change in the entity referred to;

WHEREAS, certain financial covenants in the Mortgage Loan Purchase and Servicing Agreement and the Security Agreement are required to be amended as a result of the conversion of New Century Financial Corporation into a real estate investment trust, and as a result of the proposed issuance of new shares of common stock as described in the Proxy Statement/Prospectus;

WHEREAS, Section 3.2(ii) of the Mortgage Loan Purchase and Servicing Agreement makes references to the “Soldiers’ and Sailors’ Civil Relief Act of 1940,” which act has changed its name;

WHEREAS, Section 12.2 of the Mortgage Loan Purchase and Servicing Agreement provides for amendments thereto to be made in writing and signed by the Issuer, the Seller, the Servicer and the Swap Counterparty, provided that Rating Agency Confirmation is received;

WHEREAS, Section 10.01 of the Security Agreement provides for amendments thereto to be made in writing and signed by the Issuer, the Collateral Agent and the Swap Counterparty, provided that Rating Agency Confirmation is received;

WHEREAS, the Issuer, the Seller, the Servicer, the Collateral Agent and the Swap Counterparty propose to amend the Mortgage Loan Purchase and Servicing Agreement and the Security Agreement as set forth herein;

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NOW, THEREFORE, in consideration of the premises and mutual agreements herein contained and for other good and valuable consideration, the sufficiency and receipt of which is hereby acknowledged, the Issuer, the Seller, the Servicer, the Collateral Agent and the Swap Counterparty hereby agree as follows:

ARTICLE I

DEFINITIONS

Section 1.01 Certain Definitions. Capitalized terms used but not defined herein shall have the meanings assigned to such terms in the Mortgage Loan Purchase and Servicing Agreement or the Security Agreement.

ARTICLE II

AMENDMENTS

Section 2.01 Amendment to Financial Covenants. With effect from the successful completion of the transactions described in the Proxy Statement/Prospectus:

(i) Section 3.5(i)(ii) of the Mortgage Loan Purchase and Servicing Agreement is deleted in its entirety, and the following is substituted in place thereof:

“(ii) Ensure that New Century Financial Corporation shall maintain, as of the last day of each of its fiscal quarters, a Tangible Net Worth not less than the sum of (1) $750,000,000, and (2) fifty percent (50%) of all increases in shareholders’ equity in New Century Financial Corporation attributable to issuances of common stock since October [    ], 2004¹.”

(ii) Section 3.5(i)(i)(iv) of the Mortgage Loan Purchase and Servicing Agreement is deleted in its entirety, and the following is substituted in place thereof:

“(iv) Ensure that New Century Financial Corporation shall maintain (1) its status as a real estate investment trust for purposes of U.S. federal income tax, and (2) a ratio of Total Indebtedness to Tangible Net Worth not greater than 12:1 measured on the last day of each of its fiscal quarters.”

Section 2.02 Amendment to Definition of “Cash Collateral Event.” With effect from the successful completion of the transactions described in the Proxy Statement/Prospectus, each of sub-section (i) and sub-section (ii) of the definition of “Cash Collateral Event” as it appears in the Security Agreement, is deleted in its entirety, and the following is substituted in their respective places:

“(i) [RESERVED]”

“(ii) the Tangible Net Worth of New Century Financial Corporation on the last day of each of its fiscal quarters shall be less than the sum of (1) $800,000,000, and (2) fifty percent (50%) of all increases in

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shareholders’ equity in New Century Financial Corporation attributable to issuances of common stock since October [    ], 2004²”

Section 2.03 Amendment to References to “New Century Financial Corporation.” With effect from the successful completion of the transactions described in the Proxy Statement/Prospectus, all references, including the following, to “New Century Financial Corporation” shall cease to be references to New Century Financial Corporation, a corporation formed and existing under the laws of the State of Delaware, and shall become references to the entity formerly known as New Century REIT, Inc., a corporation formed and existing under the laws of the State of Maryland:

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Section 2.04 Amendment to Reference to “Soldiers’ and Sailors’ Civil Relief Act of 1940.” Section 3.2(ii) of the Mortgage Loan Purchase and Servicing Agreement is hereby

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amended by deleting reference to the “Soldiers’ and Sailors’ Civil Relief Act of 1940” and substituting therein reference to the “Servicemembers’ Civil Relief Act of 1940.”

ARTICLE III

MISCELLANEOUS

Section 3.01 Execution in Counterparts. This Amendment may be executed in any number of counterparts, each of which when so executed and delivered shall be deemed to be an original and all of which counterparts, taken together, shall constitute but one and the same instrument.

Section 3.02 Headings. The various headings of this Amendment are inserted for convenience only and shall not affect the meaning or interpretation of this Amendment or any provisions hereof.

Section 3.03 Effectiveness. This Amendment shall be effective upon (a) successful completion of the transactions referred to in the Proxy Statement/Prospectus, (b) its execution and delivery by all the parties hereto, and (c) receipt of Rating Agency Confirmation.

Section 3.04 GOVERNING LAW. THE PARTIES HERETO AGREE THAT THIS AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO THE APPLICATION OF CHOICE OF LAW PRINCIPLES THEREOF.

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IN WITNESS WHEREOF, this amendment has been signed and delivered by the parties as of the date first above written.