The newer stock 20" rims will fit. You just want to make sure you get the correct tires. You want the diameter of the rim/tire combo to close to the same. For example, a 245/50r18 has a diameter of about 26.33 inches, and a 245/30r20 has a diameter of about 25.79 inches. Obviously you want the diameter of the new tires to be very close to the ones you took off.