I have run the powr loc before, after the clutches start to wear, they are about as useful as an open diff in a need traction situation. I run trutracs front and rear now, for that reason and they have yet to fail me, i even went from a locker in the rear to a trutrac. The handling characteristics are much better IMO. But for the initial slight increase in buy in, it was worth it.
If there's a will, usually there's a way, but then you get to that bolt that you still can't get to with two extensions, two universal sockets, and a contorsionist midget trying to help you.
1999 XJ Four door, mostly stock for now, but I am in the process of building a custom plate bumper.