Correct me if I'm wrong, but setting up the rear end is something you want done by someone who's pretty good at it. Not easy to get the backlash right at all. I helped run a shop (our family business at the time) for a few years and we usually had 4 full-time mechanics working at any given time, and out of them only a few fealt very comfortable doing this. Putting the parts together isn't all that tough, but doing it in a way that it wears properly and doesn't make lot's of noise is something different all together.
yeah there used so there broke in. and there all in the housing so all i really have to do is pull the old casing out put the used set in. the gears r all put together in the little housing so the only hard part is sliding the axels in the housing and shimming it. i pulled the whole gear set out of a 96. and there well broke in, it cant be that hard can it, and if it breaks i can just put the stock ones back in.