Wow John lot of questions! These are very capable rigs, even stock. 140k is nothing as long as it was maintained well. You'll want to do the usual checks as with any used vehicle, observe and smell the fluids, look for rust under the carpet and floor mats, is the engine compartment clean? That's always a good sign. Listen to the engine, ticking a bit is normal for these motors, check the 4wd for proper operation, the locking hubs either manual or auto to make sure they work, all interior electrical components for proper operation. Check everything and if your new to used vehicles take someone with you that isn't. With as little as 2" of lift and a 225 AT you be amazed where you can go. Through in a rear locker and go even further. Armor is always good especially to protect the aluminum front diff housing and trans and tcase. Oil pan too. The front diff housing is one of the weak points of these rigs, but there are several methods to fixing that, from a complete swap to a steel one, to special support brackets that help strengthen it. Some if it's strengths are it's quite economical to run , very durable, inexpensive to maintain, small enough to get into and out of just about anywhere, lots of aftermarket support, plenty of spare parts around,....I could go on and on. Weak points? I could say NONE! But really, they're a bit noisy inside, easy to fix swith some sound and heat insulation, and creature comforts can be lacking to someone who's used to bigger and heavier vehicles. Ride can be choppy if you lift them too much, front diff housing, did I mention that? yes and it can be fixed before broken!!! As far as the IFS goes, plenty of people here wheel the crap out of their IFS rigs and blow other folks minds with what they can do. The big benifit is they ride great too. You can find almost any info you may be looking for here, it's probably already been done or experienced so don't be afraid to use the search function. Welcome to the wonderful world of crazy Zukers!