Need Pulley info please
 

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?
Thanks!
-Trevor
:)

15 is near the JCW package , about a 5% gas mileage reduction
17 is nearing the point of needing additional mods about a 10% reduction
19 needs mods to support around 15% reduction

Pulley/Intake/Exhaust/header