I have ordered a fair amount from Quick Performance. I have nothing bad to say about their prices and support. Great to deal with. I prefer buying my parts separate and building my own junk. I had three different brand trac-loks, all with .007" runout while setting up. Finally talked to Quick Performance about it, and they recommended the toughest one they had, which was a Yukon. It set up with about .001" runout, so that was a plus. I then disassembled the unit to clean it and soak the clutches in a mixture of gear oil and Motorcraft friction modifier. The internals looked a little nicer in this unit also. Made in USA, IIRC.
I put over 1,000 miles on it between the street and a couple passes at the track. I was making around a lil over 400hp, but abused it all the time. Never a problem. Recently pulled it out for a stouter build and replaced with one of their drag spools for $85. I think for 500+hp, I would look at a locker, spool, or true trac to handle the abuse better. JMO
