Cadillac ATS Brembo Front Brake Swap

I recently have been working on a Z06 Caliper swap, and thought another option might be worthwhile.
I am thinking of using the Cadillac ATS Brembo brakes. They are a good size 4 piston brembo caliper, and can be had for $125/each from Rockauto. Or junkyards have them in the $25-50 range each. I would like to fit these to stock 298mm turbo/87+NA rotors. This would keep the swap super cheap and simple. The stock rotor size for the ATS is 321 front, 315 rear. These calipers will only get cheaper as well, as it is the same caliper used on the V6 Camaro, ATS, and CTS. In addition, I believe, the same mounting point for a 300mm rotor with V6 ATS Brembos would work with V8 Camaro Brembos on a 330mm Cayenne rotor.
Alternatively, a different design could mount the ATS brembos with the 330 Cayenne Rotors, V8 Camaro Brembos with 350mm rotors, and I believe could be used with the CTS-V calipers and 380mm cayenne rotors...
Looking for some thoughts from the community. If there is some interest, I believe I can have these made shortly after my Z06 adapters are finished.

What is the center to center bolt measurement on those ATS calps? If they could also be adapted to the 928 spindles.... Win
Cardone showing 42mm pistons and that's ideal for stock MC.
The sheeple on Renny would be on board with these adapters for sure

The mounts are 128mm apart. Mounted on a 90.5mm radius when used with the 321mm rotors. The rears have the same mounts, but with 315mm rotors. I believe the 3mm radius is changed in the caliper it self.

I have some updates here.  Some background first on what I am working with:

Camaro, CTS, and Corvette all come standard with three brake options, and I believe they use the same calipers for all these.  

Small (4 piston brembos):
320mm rotors on base CTS, V6 Camaro, base C7 Corvette

Medium (4 piston brembos):
345mm rotors on Uplevel CTS (AWD), V8 Camaro, Z51 Corvette

Large (6 piston brembos):
370mm rotors on CTS-V, ATS-V, ZL1, and Z06 Corvette.  

The large are the massive 6 piston units.  These would only work with 370mm or larger rotors on our cars.  

I ordered my self a caliper from the medium bunch.  It's about the same size as my Z06 caliper.  Except I paid $60 shipped to my door for a unit with under 1000 miles.  It's a beautiful caliper.  The unfortunate news is that the 350mm cayenne rotor is too fat at 34mm thickness...  Looking at the parts catalog at rock auto, it looks like there was a 358mm rotor option for the Cayenne.  I ordered one and plan on making a bracket for these CTS calipers on that rotor.  

I will soon order a caliper from the small bunch and make a bracket to fit that to Cayenne rotors as well.  Although, I think once again we will have to use the rear 330mm rotor for that, since it's only 28mm thick, as these calipers were only designed for 30mm rotors, not 32mm as the cayenne is.  





Comparing this picture to the Z51 brakes on a Corvette, I'm almost positive they are identical...  You could powder coat these red and put a Corvette sticker on them and sell them for $600/pair...

I have some updates on this. I ordered the small ATS calipers (same as C7 Corvette base and V6 Camaro). Unfortuntely, these will require too much grinding to clear the caliper ears with 330mm Cayenne Rotors. The larger CTS calipers (same as Z51 Corvette and V8 Camaro), will work with the 358mm Cayenne rotors with minimal grinding though.
I also tried the small ATS calipers on the 358mm Cayenne Rotors, and they work great using my already designed C6 Z06 caliper bracket. This is good news, as these use the same pads and piston sizes as the CTS calipers, just a slightly smaller body. These will clear 18" wheels.

Here is a picture of how much grinding would be required on the ATS calipers for use with 330mm rotors and 17" wheels:



Here is a shot showing the small grinding required to make the CTS calipers work with 358mm rotors on 18" wheels.



And finally, the ATS calipers mounted on my mock Z06 adapter:

Unfortunately, the small ATS calipers will not work... They are made for too small a diameter rotor, so they need to sit too far out on the 358mm rotor to clear the wheel. The only way to make them work would be to modify the spindle itself, and this is probably more work than its worth.