You'll need the ECU and wiring loom for the XR2i engine, i think the engine loom is a separate loom on this car so that should make it a bit easier. That means that all the engine sensors will run directly into the ecu and you will only have to wire up things like the tachometer etc which your one litre probably didnt have. You will also need the electric fuelpump and/or fuel tank for an XR2i and the associated wiring and relays etc. You'll also need the proper exhaust and uprating the brakes is also recommended.

I'm unsure on the differences between the driveshafts but if your car ran with those wheels before it will be exactly the same whatever driveshafts you use as it's the suspension that dictates how far out the wheels will be.

To be honest it would be easier and cheaper to just buy an XR2i in the first place, having done a similar conversion though there's nothing more satisfying that when you fire it up for the first time and all the hard work pays off.

If you can keep costs down by doing most of the work yourself then you should go for it, otherwise just buy an XR2i and start from there. It'll probably be less to insure a standard XR2i than a modified one litre anyway!

Hope this helps

Cheers

Alan