A couple of comments that I can make with a fair bit of certainty... since I've had hands on experience...
- The Pfadt Racing Hubs are exactly the same as the the SKF hubs - there is no difference. They are simply doing a better marketing job.
- The SKF Racing hubs are materially different from the stock Corvette (i.e. non-ZR1) hubs. There are additional bearings (on the (in the?) outside shoulder) and the shoulder itself is larger diameter to accommodate the additional bearings and improve the pressure base.
- While the materials used in the SKF and stock bearings may be the same (I can't prove it one way or another) I believe that the process is different - the SKF hubs are visibly different.
While I understand the desire to be thorough in looking at a "new" product - I really can't understand why the SKF bearing would be the part in question. I think that it is safe to say that it is the least unknown or unproven commodity here.
I have to hand it to Tom and Blake and co. for designing a system which takes advantage of a reliable, street and track proven component and adapting to to "our" applications.