I just did one of these myself, the donor car was also a MK3. If you're also taking the Mk3 gearbox (as i did) you'll need a speedo cable, you'll have to do a bit of fettling to fit the new gear shifter and either modify your pedal box to keep the hydraulic clutch or get the necessary parts to convert to a cable clutch. I managed to do the loom myself too (with a lot of help from rubjohnny - thanks again for that!) which wasn't too bad, especially considering I'm red/green colour blind! Best of luck!