[BoostJunkie]

Well, I don't wanna be a ****, but 90% of the car forums you go to will tell you to "search" for obvious repeater questions(things that have been asked numerous times in Forums) but seeing how this is a slightly diff forum, basically if you looking for small performance upgrade like 5-15hp, then I don't think you really have to worry about effecting your street legal ability, unless you live in Cali, then I got no clue. For what your asking, full exhaust(header+midpipe/downpipe/cat+muffler), cold air intake, with a reflash would probably surpas your 5-15hp goal even if those are 5-15whp. Turbo vehicle's are even easier, bigger exhaust, Boost Controller, reflash, intake and depending on the engine/vehicle, you can see 25-100whp gain, but that all depends on the engine, hope that helped