things like wheels, exhaust, pod, suspension can all be engineered. it doesnt cost much. the cheapest ive been quoted was $250 from a friend of a friend. max you'd pay is 300-400.
my car sits around 50-60mm off the ground, its bright yellow, and its got a 3" turbo back feeding into a 5" tip. i havent been pulled over since i took my wheels off (in my sig). so it all depends on how you present the car. it scores big points with the popo.
we really need an engineer that does engineering for sau members. now THAT is a damn good idea.