Can any of you Help me?
 

Hey, how is everyone?
I just purchased an '03 mini cooper s. I've been looking into some quick things to make the car a bit faster. I've been looking into the supercharger pulleys that have been reduced to 15, 17 or 19%. I'd take you guys opinion over the markets, could you explain each one of them to me please? and how bad do they effect your gas mileage? Any other recommendations?:D
Thanks!
-Trevor