pretty much everything needs swapping over in the engine bay, brake servo, front calipers, brake lines to rear of car + beam and discs assuming you want to fit rear discs, (recomended to at least swap the rear beam as it has integral anti roll bar) lines under the car, both fuel pumps as well as relays from fusebox and wiring to the rear of the car (or just chop out the fuel pump loom from the donor) The actual tank does not need to be swapped but probably just as easy too since fitting the lines between the lift pump & main pump is tricky without dropping the tank at least a little.
Wiring depends on if the G reg 1.3 is actually a 90spec, or a late regged pre-90. If the hazard switch is on the column then its a 90spec and the engine/rear loom will plug in, if on dash its a pre-90 and for plug n playness the entire car loom needs swapping