I'm running the Corsa system on my H3. Interior noise level is acceptable for use as a daily driver. Freeway cruise sound inside is close to stock (in the range of 70-85mph). Exterior sound is kind of like a BMW straight six, actually sounds good. No rice burner 4 cylinder sound, no V8 rumble either. Power increase can barely be felt, just a little extra is felt pulling long hills in 3rd gear (auto tranny). For serous wheeling you will need to have a muffler shop modify the tips to make them removable, otherwise they will probably drag.

I'm using stock intake, don't care for the sound and suspect filtration of aftermarket systems.

S.