IIRC, the GT500 Brembos fit with a lot of 20" wheels correct? I have 20x8.5" in the front but off the top of my head I don't know the offset. Is fitment on 20" wheels iffy?
Its not the hight that is the issue, its the width, the calipers get VERY close to the spokes of the wheel, they wont fit Foose wheels. Whats your offset?