I think if anyone just records their car and you put it in the flash intro, it will sound real cheesy. I think you need a digitally altered version of the sounds where someone already made it sound more realistic (now that I think of it, can you just take the sounds from the fast and the furious?). Their fake blow off sounds were crisp and clear, and so were the exhaust sounds like when they take off from the street race with 4 cars lined up. I personally hate flash cus it's a pain to do (I've only done one flash intro though). Good luck.