I have 17's on my ride and that is about as big as you can go and still maintain an agressive look. The bigger the wheel, the more inertia it takes to get going. My wheels weigh 15.5lbs each and weigh as much as the 16's I use to have. If you go 18 get ready to rub, even if the offset and wheel size is dead on, it's gonna tuck right under your fenders and when you hit a bump your gonna know it and it will begin to bug the shit out of you.