I did the CPP kit a long time ago. The first kit you posted (less the booster.) If I remember correctly, it is based on a late 70's Camaro set up ( or something similar.) They are one piece / hub type rotors that come with a a collar that fits on to your original spindle. That collar allows for a tapered bearing to be used on your spindle. You can see the collars in the picture. I pretty much ran that kit on my '49 without a booster until I clipped the front end with a Camaro clip. 10-15 years ago? I've never had a problem with CPP and they seem to have knowledgeable folks there. My most recent purchase from them was a firewall mount booster / master for my '52 'Burb. No issues so far.
