Just buy a cheap GTi.. Its MUCH easier than trying to gather all the parts individually, and I promise you'll overlook something..
You'll need:
-Complete engine (including all parts, all ancilleries, belts, both manifolds, injectors, sensors, flywheel and clutch etc).
-GTi drivers side engine mount.
-GTi gearbox mount (2 pieces).
-GTi under engine brace.
-Complete engine loom with all plugs. There's 3 parts to this, power loom, sensor loom and the Injector loom.
-GTi clocks.
-GTi ECU, ignition barrel, door locks, key and NATS IMMU box, now its vital these 4 items are a matching set..
-GTi gearbox.
-GTi shafts both sides.
-GTi wishbones & hubs both sides.
It'll also be wise to upgrade your suspension and brakes, and get GTi strut braces to ensure the car's strong enough.
You also need to think about Bolts.. I know it sounds stupid but a missing bolt can halt your build for days, even weeks!
You better thank me for this bitchhh lol, took me a year's worth of research to do my project as Andy S never did a proper write up so I had to find everything out myself pretty much.
Just use my thread as a bible.. And I'll give you another tip.. DO NOT TAKE SHORTCUTS.. buy ever part possible you can afford brand new.. Don't use old parts or you'll pay for it double at a later stage.
Good luck.
Joe