You can uses the same tank just blank off the feed and return at the bottom.
Would be easier to just swap the loom for a g40 loom or just take the bits you need from it as the rear light plugs will be differant possibly, but if you have a wiring diagram and basic electrical skills you can work out and wire in the pumps yourself but it's will probs be cheaper to find a g40 loom and a lot less hassle
