Originally Posted by ChitownM3
It is very hard at this point in time to get 500 hp out of a 4.0L v8.
NA state of the art for production engines is F430 and GT3 both around 115 hp/l. Even at 120 hp/l (quite an impressive jump) the M3 would only be at 480. I'd guess the CSL will be about 450-460 hp from the same 4.0l.