As manufactured the Cobalt & HHR’s had 2 wheel patterns. They were 4 lug X 100mm and 5 lug X 110mm. Either pattern is usable on the GTX. Both patterns are popular on many non-GM cars, making it possible to select a very wide variety of wheel styles, and sizes. As stated earlier, Berrien Buggy can provide front brake rotors drilled and tapped for either wheel pattern.