The ATS-V has 15.1 inch front Brembos with 6 piston calipers, which are huge. Two piece rotors also, so should be very similar to the CT4 V BW set-up. I've always been amazed that they were able to fit all of that into 18" wheels. My guess is that the brakes are very similar. No-one ever complained about the braking performance of the ATS-V. The dealership may have some wheels to try it on first, but I bet they will fit just fine. Remember that the fronts and the rears are different, with the rears being wider and more deeply dished. Plus, the rear brakes are smaller, with smaller, 4 piston calipers, so the front would be the area most likely to have a fit problem, if there is one.