Would the wangler rubicon transfer case from the last model be a direct swap into my xj? I got a 1996 xj and I was thinkin that cause that case already has a better low range and does not have a slip yoke (not sure correct me if I am wrong) it might just be easier finding one in a wrecking yard. What would be the differences?

Yes, it will fit. It will be Badazz, but your not finding one in a wrecking yard.

any other upgrades that would be a easy direct swap?

the rubicon 241 is easy and direct, it is just privey 900-1000$
SYE for 231 is like 200.00