Originally Posted by evolution
It depends what you put on it but nothing will make a big difference. You won't really pull on a stock S2.
Sadly there is no 'best' part, but here is the opinion that floats around to my understanding:
Biggest asset is driving skill. Other than that, I know I am repeating myself but go with final gear ratios. HUGE difference and good value!
werd... go for 4.57 or 4.77 gears. Best bang for your buck. Anything else NA will just make you louder. Not that that's a bad thing though...