The back-end and the front fascia had minor changes. These changes happened regardless of wether they are different cars are not. Therefore it doesn't necessarily mean that the base Tesla Model S isn't the same for both version.
What does make the most sense?
1: Saleen managed to borrow 2 different Tesla Model S P85 which has been out of production for the last 5 months.
Or
2: Saleen managed to borrow someone’s Model S P85 to make the 416 display car, but when Tesla discontinued the P85 with its 416 hp, Saleen was stuck with rebranding everything, so they changed the P85 borrowed for the 416 display, which had become useless, and made it into the “GTX”.
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