Has anyone used or know anything about the Bolt-on Rear Disc Brake Kit #91031919 for $350 ? When I install my 8.5, I was thinking about converting over to disc brakes and saw this kit. I looked at the instructions and it didn't look to hard to do but was wondering if the kit had everything for the complete swap. Fancy conversion kits are big money so I was wondering if I was missing something due to the price of this one.