to put 4wd onto your mk2 you'd need to swap the floor pan and gearboxs over. lots of work. there are a couple of articles on the web about it. if you can't weld yourself I'd forget it. the labour charges alone would be silly. Designa Dubs quoted me ?10000 to put 4wd on mine!
a mate bought a syncro for ?300 complete from our local. and btw, all syncros were 5dr unless otherwise converted.