Originally Posted by RX8Soldier

there is a stickie at the top of the wheel and fitment forum that should have all your answers...

Please familiarize yourself with the stickies in each sub-forum.

Originally Posted by RIWWP

Wheels
(No impact to warranty)
Wheels are more subjective in nature than most upgrades, as they tend to be selected more for appearance than for performance. However, there are three factors for performance to keep in mind:
- Wheel weight: More important than other metrics, a heavy chrome wheel will directly reduce your acceleration, lengthen your braking, and make your shocks and springs work harder. A lightweight wheel improves all of these dramatically. The Enkei RPF1 is the commonly selected wheel, being both light and fairly cheap.
- Wheel width: Increasing the width of the wheel allows you to run a wider tire without stretching (which can be dangerous with high lateral Gs). However, wider is only better to a point. Going wider means going heavier, and you can start losing steering feel as you go wider as well.245-255 is typically considered to be the sweet spot with increased grip before the steering feel starts to fade.
- Wheel diameter: Assuming that you size your tires to have the same overall diamter, a smaller diameter wheel will mean an increase in tire sidewall, which means an increase in sidewall flex. This isn't immediately terrible, as flex can be very important in the correct amounts. This can also help to absorb road/track imperfections as a 'second spring'. Smaller diameter wheels are lighter, and tires are usually significantly cheaper. Going larger reverses all of this.