More specific about what? If you already have 17x9 wheels then you'll need different wheels with the 13 inch kit since the hub surface is moved out about 0.750 inches. The 13 inch kit is designed to work with Mustang rims that have the 5.72 backspacing. On some cars you need to go with even more backspacing than that. It takes some real effort to cram big brakes and big tires into the small space that the factory engineers left us to work with.