I reckon Cass (DR Diff) is about as straight up as you will find.
I'm an 8.75 "novice" and I've recently purchased two pinion install kits, and three sets of gears and brake drums from him for myself and a couple of mates.
Cass has been nothing less than super helpful and and patient with my "learning curve"
If he's selling those centres...you can trust them I reckon.
I did, from 18000 miles away, and Ive got no concerns. :salut: