Of course the D30 is junk.... Not. Tons of them running Moab daily. As long as you aren't crazy on the skinny pedal it survives just fine. Forget the D35 in the rear though, it isn't any better than the 7.5" Ford rearend. If the ZJ has the D44, it isn't great but better than a D35 anyday, but really limited gearing choices. Truss the housing and its not too bad.
Naturally, I'm a Jeep guy, with a Grand Cherokee. I wheel with folks that still have their D30s under their Jeeps and they aren't easy on them.
And I'm puttign a High Pinion D30 from a Cherokee under my Ranger. Using TJ long arm front lowers, JK front uppers with some mods, and will fab a trackbar and mount. Why this D30? I got it for free. The coil buckets are SO very close to a match (about a 1/2" difference), same bolt pattern so I can keep my wheels. The driveshaft from the Ranger will bolt right up to the D30. The HP D30 is a littl stornger than the low pinion...
Now, IF that ZJ D30 has the CV joint axle shafts, get something different, or get some better 297/760 jointed axles at the junkyard.