Size your wheels to your brakes, just large enough to clear. Anything larger is just extra weight, with a larger
moment of inertia, reduced comfort, and reduced pot-hole/kerb protection for the rims.
If you want to go all out, use 17s on the front and 16s or 15s on the rear. Honda did this for their 2010 Super GT GT500 car, the HSV-010, using 18s on the front and 17s on the rear.
http://www.autoblog.com/2010/01/18/o...cs-on-hsv-010/