Mark, I have a "kink" in the shiney bone I used right where it expands out from the bone and begins the cup, and it was a TC3 unit. I haven't looked at too many other manufacturer's units yet because these have worked pretty well. The Pro 4 is pretty durable, just remember that with ANY shaft car the ring and pinion gears are consumable items that should be replaced occasionally even if they don't strip out. Other than that I've only broken a few parts since February with the Pro 4. The oddest was a broken ball stud on the opposite corner that I actually hit the wall with, and other than that I've broken a couple of A-Arms and C-Hubs. Just mod a Buds TC3 bumper and most breakage should be taken care of.