i agree that swapping in another rear is worthwhile. if you want to run anything larger than 33's or 34's, you're going to need a d44 or 8.8 because of the gearing available for the 8.25 (notice i'm not even considering the d35). it only goes up to 4.56 which is good for an auto on 33s or a manual on 34s. if you plan on staying smaller than that, a 29 spline 8.25 is plenty solid and it's an extremely easy swap, a direct bolt on. i'm not 100% sure, and someone help me out here, but i believe that a d44 from an 87-89 xj is also a straight swap. just some options to consider. all these axles can be picked up pretty cheaply at pick and pulls too. there's also some decent write ups on junkyard dissasembly (cutting, breaking things, etc). and thoughts on the d30 too- if you plan on running anything monstrous you're going to have to truss it because they bend relatively easily. lots of things to consider. hope this helped.