S13 or S14? I have the TT wheels and I needed a 25mm spacer up front to run coilovers. They fit fine on a stock suspension. The fronts should be the same as the NA 300ZX wheels. I am running a 225/45/16, but I want to put some 50 series up front since I have 255/50/16s in the back and I think it looks kind of wierd.