ahhhh where to start. Its not going to "bolt in" or easy. Ive done a mk2 dash into a mk1 and I wouldn't do it again. It takes alot of putting it in, pulling it out kind of tweaking. Having never dealt with a raddo dash, I imagine it would be just as much as a pain in the ass, if not more.
Buuuuut, it is high on the cool factor, and if you feel like pulling the dash and putting it back in about 30 times, go for it.
Vwvortex is a much better place for this question.
W terminal wont work on vr6 tach unless you rewire the circuitry in the tach. Has to be a diesel tach.