How 'bout just buy the car? Then put it on Ebay with an openning bid right @ MSRP. You will surely get more for it than that, hence effectively selling your spot as you intend to do. In fact you'll probably make a hell of a lot more that way, and you probably won't ever even have to make a payment on the car. It will tie up your credit for a bit I suppose, yes.
Or even better:
Isn't it the case that you now feel as though you CAN afford this car? Yes that's it! Everyone can discontinue this heated discussion since MBITION has now decided to keep his spot and buy the car. No harm, no foul. Right guys? MBITION is going to make an honest attempt and keep his "promise" to the dealership that he'll purchase and take delivery of one 2008 M3. What happens after that, of course, we cannot say. If he registers a new ID on Ebay and hawks the car right away, well, that would be dirty, awful, rotten, and deceitful!
But we'll never know about it, so we can't call him out.
Damn, and now what the hell are we going to do with all the soap-boxes lying around here.
Good luck, man!