Okay..I've purchased a biturbo for my a55 sprint. What exactly does an aftermarket exhaust do to achieve more mph..will I do more harm than good to my motor. This is the first mod I've done..not counting a locking gas cap...I can rest now knowing bums and drunk college students will have a much harder time pouring crap into my tank..PS anyone know where I could find some folding rally pedals. I called 1977 peds since they're out right now..says they'll let me know when they get em..any other sites have any?