to be honest i think the brakes are compensating for the 18's. the larger diameter gives you a slight bit more traction but that's about it not much considering the negative aspects.

i have a few questions for you.

do you have ABS? if not how quickly can you lock your fronts? one would think with rotors that big and 6 piston calipers you would have beyond enough force to clamp the rotors dead even with 18's.