You'd be better off using the sapphy stuff, as the arb doesn't do anything really on the 3 door, the shorter sapphy one makes a hell of an improvement, just need to weld 2 points on chassis type bit that holds rear diff hanger for the bushes/clamps for the arb that's all.
There are 3 different tanks used on 3 door and 2wd sapphy, but all fit each other, most of the difference is on the upper edge nearest the fuel filler corner of the tank.
If you have a few to choose from choose a "made in canada" one, as have better swirl pots.
tabetha