Yup. This is exactly why I was curious what Baer setup the OP is running.
To the OP... You don't need any type of brake kit with the ATS spindles. Stock C5/6 Corvette calipers bolt directly to the ATS spindles. Also, I am really curious as to which Baer setup you are running. If you are running the Alumasport setup with the two piston PBR calipers, I will let you in on a little secret.... THEY ARE C5 calipers. Touring Classics, KORE3, the Baer Alumasport.... ALL OF THOSE ARE USING THE PBR TWIN PISTON CALIPER.
If you are planning on running the Serious street Baer setup, well those are C4 corvette calipers. Also PBR, with slightly smaller pistons. The Touring Classics Hybrid kit uses these also.
I hope I don't offend anyone, but the ONLY Baer systems worth the coin are the ones using their new mono block caliper. All of their other kits are just using off the shelf PBR Calipers with their logo emblazoned on the face.
Lastly, if I were a first gen owner, you can guarantee that I would have a set of AFX spindles. Beautiful pieces. And the benefits provided are unparalleled.