AX5 isn't bad behind a 4banger, don't let anybody talk you out of it. You wouldn't want it behind a 4.0L or v8, but it's all relative.
I've got quite a few power mods, beat on my heep pretty hard, and the AX5 is holding up just fine. Most reported problems relate to synchronizers, which is the factory's fault for using and recommending the wrong fluid.