[theastronaut]

I've heard from a couple sources that the CPP Modular spindles flex and can cause pad knock back if you're cornering hard on the track with sticky tires. They're also very heavy. The ProSpindles should be much much stiffer with no knock back issues and a lot lighter since they're aluminum. CPP is suppose to be making their own version, but I haven't heard a release date. I'll probably switch my Modular spindles out just for the unsprung weight reduction. There is a forged aluminum hub that can be ordered for the Modular spindle so you can use slip on rotors, I did that to adapt 2nd gen CTS-V brakes onto my '66. It's a very heavy setup though.