suspension is same on XR4x4 / 4x4 cos (well, interchangeable)
hubs different on all of em
diffs on 2wds are small nes + no slipper,
4x4 rear diffs the same (2.8/2.9)

beam+subframe etc. dunno im pretty sure the rear beams on the 4x4s are the same, but dont know for sure