The MP kit wasn't much. The only unique part was the K member and there isn't much to it. The rest was off the shelf parts. I believe the brake/spindle setup was Grand Caravan stuff for the bolt pattern. Spring can be wound at any competent spring shop for the added, if any, weight.

There is nothing in it for a rear suspension.

These guys used to make a kit, here are pics.

http://www.exlinecustomauto.com/clientscars.html#anchor_58