i just did this swap on my mk1, u can use mk2 front belts as well, but make sure you get all the hardware and the receiver, since u have a 4 door i'd get stuff from a 4 door, just in case. as far as rear shoulder belts go, i am pretty sure there is a threaded hole in the c pillar for them, i don't know what will tho since i never saw a rabbit with rear should belts, how ever i am almost certain that all the euro cars had rear shoulder belts, i know i have seen them in mk1 jettas, mk1 jettas even have a slot in the rear shelf where the belt would go through, euro jettas even had a center seat belt.