I would choose a ZJ over an XJ, but then again I'm biased <img src="/forums/images/graemlins/smile.gif" alt="" />. Both are fairly capable platforms for a unibodied vehicle. If properly set up both can flex equally as good on short arm lifts, long arm lifts are another story and if properly set up the ZJ's rear 4 or 5 link (depending on the lift) can outflex an XJ's leaf packs. Like Cuervo said try to get a newer one if you can for the stronger head castings and more power, also the D30 from 96+ came with 297X u-joints (same as D44 front u-joints) instead of the smaller 260x joint pre-96 jeeps. In the rear axle department it is pretty much a toss up, pre-96 XJ's came with the D35's, 27 spline chrysler 8.25" or the sometimes hard to find D44 (this only came on XJ's with the towing package between the years of 87-93 I believe), post-96 XJ's came with the D35 also but the 8.25" was upgraded to 29 splines (stronger). Pre-96 ZJ's only came with the D35, post-96 ZJ's came with a D35 for the I-6 engine or a D44a (30 splines but with an aluminum center center section and c-clipped axles) for the V8's. Or get whatever for the rear and just swap in a Ford 8.8 from an explorer as it has a Stronger ring gear than the D44 has 31-spline shafts has about the same WMS as the OEM axle can be set up pretty easy, upgrades the rear with disc brakes for the XJ and can be found fairly cheaply at a yard for around $100-$200 bucks compared to what most yards want for a D44 out of an TJ or XJ which usually run $400+. With front axles the XJ's win it because they have the high pinion D30 (stronger ring gear) versus the low pinion D30 that ZJ's came with. T-case wise the XJ's came with the 231 or the 242. ZJ's came with the 242 (I-6 engines) or the 249 (V8 engines), if you go the ZJ route with a V8 the 249 full time case can be easily swapped out for a 231 or a 242 so it's pretty much up to your personaly preferance. Also if you like comfortable wheeling the ZJ beats the XJ hands down <img src="/forums/images/graemlins/kewl.gif" alt="" />
Here are some pics of my junk... Specs below.


Hope this helps,
Fred R.