You can certainly do as jon@work says, but having had a xr4i myself I would advise you to do a little welding and make attachements for the sapphire type rear arb, the 3 door cossie one, like I used is not worth the effort of fitting imo, though better than the 4i one, it's still pretty useless being too thin and long, sapphire 16mm(2wd),18mm(4wd), or escos 22mm improve it no end, though if you have been able to put up with a lack of rear arb for that length of time anything would seem ace even the std 4i one!!
I also had a tow bar on my 4i with the 18mm rear arb from a sapphy so there is room, I merely welded two plates on the flat "chassis" type bit above/behind the diff to locate the arb mounts.
tabetha