It’s important to pick a wheel that fills up the wheel well nicely. You don’t want the wheel to be too narrow or it will lack traction and look goofy. A wheel that’s too wide can rub the inside suspension components or outside fender, or both!
The centerbore is the hole in the backside of the wheel. It must be the same, or larger than the vehicle hub size or the wheel won’t fit. In 99% of cases, the centerbore is larger (often 73.1mm) and adapted to be perfectly center on the vehicle by use of a hub centric ring.
Lastly, if all other criteria are met we look at the spoke design of the wheel, and whether or not it provides adequate caliper clearance. X-factor isn’t easy to quantify with a number, but a flat face or concave wheel often has much more room for a caliper than a deep dish wheel with a lip. High performance vehicles such as WRX, STi, EVO, or other cars with Brembo calipers need to pay close attention to a wheel’s X-Factor.