The xr4x4 shafts have no groove for the clip, and are about 12-15mm longer than the cozzy items, fine to fit them if the car is lowered 40mm or more, but i tried to fit them to mine lowered 25mm and they were too long! when cornering hard they would give a massive judder as they couldnt move in the joints( too long) so as a rule standard shafts up to -25mm, just leave the diff clip off to allow a little movement, xr4x4 items - 40mm
and always use vibratecnics engine mounts as in the long run it saves the shafts as it reduces engine movement.

Hope this helps.