The Black Diamond kits were actually very good kits. I have a few freinds that ran them and they preform as good if not better than TJs.
They are weld on. Really not sure if you can still buy them or not.
The Pro Comp kit that you are asking about is a bolt on kit.
I have only known one person that had it and he ditched it for a SOA.
Part of the problem with it besides lack of articulation was the fact that if you wanted to go to bigger axles it was useless.
93 YJ SOA 2" springs front, XJ springs rear w/main leaf added, High pinon 9 inch rear detroit locker front Dana 44 ARB 4.56 Gears, 36 inch Irok tires too much to list. www.mijc.org