I guess it depends on how you use/wheel your XJ. But having gone wheeling with the stock BFG Rubi tires (32x10.5), then swapping out to a 33x13.5 Irok, I've managed to get to so many different places. Now that's an extreme difference. But even the BFGs vs my old Nokian MTs (33x12.5) allowed me to make it up trails that my buddy in an identical rig couldn't (stock BFGs). Especially in snow and loose dirt/rocks, where I couldn't before. It's not the height that's helping (that whole 1/2 inch), but the fact that it's wider that distributes the weight better, that allows me to go that little bit further.
Now if this is primarily a highway vehicle that never sees gravel, then go with the narrow one. But if you do occasionally wheel it, or want that more aggressive look, then grab the wider one.