The car will be nothing more than a toy, he has LOTS of cars and this is just another one in the collection. The 2003 is nothing special, its just a low mileage rusty New England car picked up for short money and runs great, not the end of the world sacrificing it. We have done several LS and Coyote swaps, harnesses and computers are readily available. I don't have any connections in the Mercedes world as far as who does something like this. WE generally build drag cars and modified American Muscle cars as well as one of a kind projects for this customer. (we are currently building him a 53 Pontiac convertible with a Chevy Trailblazer engine) AS far as suspension and rear goes I have to get both cars in the shop. It would be nice to use the 2003 rear to keep it a complete package.