Mopar Muscle Association UK

Nige, I was considering this in the past so I have kept my eyes open for the last few years to see what feedback they get.

Bottom line - opinions vary but the Powertrax does seem a bit severe compared to a suregrip (but probably not an old style Detroit locker), and a few people have raised questions as to their durability. I think they are primarily used by the 4x4 crowd.
One of the Mopar mags did a build on one, but it was in a low power application on an 8 1/4 IIRC. I've heard a few people rubbish their quality, although some have used them without trouble.

Don't forget both the cone-type and now the superior clutch type SG are available new now, so that might be a better bet.
I ended up going with a used clutch SG.......

Depends on the power and weight of the car, the detroit, although as said is a little severe will handle the most, no doubt, also the'll stand abuse on the strip whereas the others will only stand so much