well the interior dimensions are all the same, only difference is location of the pillars. im guessing it might just make it a pain in the sack for people to get in the back seat, but luckily all i carry around back there is fit, flexible, slam pieces
This cage was designed using my 2dr, and a friends 4dr. For it to fit perfectly, in either style, the main hoop needs to be stretched slightly wider, more for a 2dr than a 4dr. Not hard at all with a porta-power. also, the main hoop is about 2 inches low, so that needs to be added to the bottom of the main hoop, and the 2 legs that go to the floor in the front. Also, the legs that go to the floor in the front are better if it goes straight down to the floor, not bent to tuck back in a bit. Again, very doable with 2 mins on a bender. If you want more info on tips/tricks with this cage, hit me up. It has served as a good base for other additions in my XJ.
Also I think a critical item is tying in the front seatbelt mounts. The main hoop runs close enough to them to tie in easily.
Go look at my "Geriatric Dinosaur" thread in this forum... you can see pics of how I set up the cage in there.