Exhibit 10.4

From: Diarmuid O’Connell

Sent: Friday, October 01, 2010 11:39 PM

To: jdidonato@huronconsultinggroup.com; Mike Taylor

Cc: KMcKenzie@nummi.com; jbeard@huronconsultinggroup.com; [Email address intentionally omitted.]; [Email address intentionally omitted.]; jpotts@nummi.com; PAitelli@mofo.com; HKang@mofo.com; MSteel@mofo.com; charding@telsamotors.com; dedwards@nummi.com;

Deepak Ahuja

Subject: RE: Letter Agreement Extension

John -

Acknowledged and agreed.

Best, Diarmuid

From: jdidonato@huronconsultinggroup.com [mailto:jdidonato@huronconsultinggroup.com]

Sent: Friday, October 01, 2010 11:36 PM

To: Diarmuid O’Connell; Mike Taylor

Cc: KMcKenzie@nummi.com; jbeard@huronconsultinggroup.com;

[Email address intentionally omitted.]; [Email address intentionally omitted.]; jpotts@nummi.com; PAitelli@mofo.com;

HKang@mofo.com; MSteel@mofo.com; charding@telsamotors.com; dedwards@nummi.com

Subject: Letter Agreement Extension

Diarmuid and Mike:

Please acknowledge and agree to the below by return email:

Re: Letter Agreement dated May 26, 2010 by and between New United Motor Manufacturing, Inc., a California corporation (“Seller”), and Tesla Motors, Inc., a Delaware corporation (“Buyer”) (the “Original Letter Agreement”), as amended by that certain Amendment No. 1 to Letter Agreement dated June 15, 2010 (“Amendment No. 1”, and together with the Original Letter Agreement, the “Letter Agreement”). Except as otherwise defined herein, all capitalized terms used herein but not otherwise defined herein shall have the meanings set forth in the Letter Agreement.

The parties hereby agree that the Closing Date, as originally defined in Section 4(a) of the Letter Agreement, is hereby amended such that the Closing Date shall be October 8, 2010, or such

other earlier date as Buyer and Seller may mutually agreed upon in writing. Nothing in this paragraph shall be construed as Seller waiving any rights or remedies Seller may have under the Letter Agreement in the event Buyer fails to consummate the Closing by the Closing Date or that Seller is agreeing in advance to an extension of the Closing Date beyond the extension provided in this paragraph.

John C. DiDonato

President and Chief Restructuring Officer

NUMMI

Cell phone: [Intentionally omitted.]

Email address: jdidonato@huronconsultinggroup.com

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