Ok, here is good one. I am in the process of upgrading my brakes to GT3 MkII (04-05). Everyone told me I needed to buy the GT3 front uprights and associated bearings, bearing car, etc. in addition to the calipers, rotors and pads. Today, I took off the "C2" uprights and low and behold I cannot find a damn difference on them that would make the brakes not work with them. There are some very minor machining differences on how the inner brake dust shield mounts, but the caliper bolt holes are the same size, on the same centers and the same distance from the wheel hub. Everything lines up exactly the same. My calipers should be here on Tuesday so I guess I will know 100% then. Any one know of any differences????

 

can't wait to hear how everything ends up! i was wanting to do the same thing later on. SO i am eager to hear everything you had to do can you post pix of the swap??