2.0 8v or 16v? Either way you can run it all off the stock managment and use the MK1 sensor wiring, all the mk1 mounts & gearbox will bolt to the 2.0 block. If its an 8v the stock 8v zaust will bolt to the engine, but try to get a GTI/Rocco 6 bolt manifold/downpipe if you have the older 'toilet bowl' setup, it flows a bit better.
If its a 16v you need to find a 16v MK1 conversion setup, either using one of the conversion 4 branches out there, the rare 16v rocco setup or a custom made setup. I have the top half of a 16v downpipe welded to the bottom half of an 8v MK1 downpipe, takes a bit o jiggery to get it to the right shape tho.
To run the MK1 dash you need to bin the MK3 coilpack setup, which is worth doing as its rubbish anyway! Reason is the MK3 dash gets the revcounter signal from the ECU, and this signal is not compatile with the MK1 dash.
The MK1 dash gets the signal from the coil, so you keep the old MK1 coil & wiring. You may need to fit a MK2 coil if you have an old MK1 coil without the middle pin in the king lead hole.
Then you chop off the 3 pin MK3 coilpack plug, tie back the black and the brown wires so they dont short anywhere, and splice the other wire (green/red iirc) to pin 6 of the MK1 TCI-H unit. The TCI-H unit is the 7 pin thing bolted to the metal bracket in the scuttle area, linked to the coil.
I hope that last bit makes sence!
