I believe thats a fullwidth. I guess you could say anything would fit under a TJ, but if you want to keep it roughly the same width as you're running, then go for waggy 44s. But if you want a wider width, go fullwidth. Its not so bad.
the j4000 front would be a passenger drop, so unless you'd be swapping tcases or retubing it you might want to check into other axles. like it was mentioned earlier, wagoneer axles will work. there's actually a set in the classifieds