I am new to Gc's but have extensive Wrangler experience , the main part to worry about with snorkel's is the way it would mount to the exterior of your jeep . The 4.0 or any other motor mounting up would be just a matter of rerouting the flexible hosing ( and flexible means what it says ) . You might have to purchase a little bit of extra flex or you might have too much , just make sure you seal it up proper .
I would just make sure that your getting the snorkel from the right years ZJ=Zj , WJ = Wj , just to make sure that the lines outside are as form fitting as you can make it . I don't think it would be off much , but if your picky , then could be a deal breaker .