Well, Have done a 2.9VR into Mk2 Golf conversion, and done a bit of research. I'm confident the rear axle will fit, I assume this because the Mk3 VR axle will fit into the Mk2, which are more or less the same chassis, obviously the running track is wider, which I guess your aware of. Another thing to take into consideration is the raidiator, not sure, but don't think this will bolt straight in. You should be able to make it fit, although think you could get away with using the original rad, will get you going at least, have heard of other people using these without a problem, although would change to the the VR one as soon as.
I disconnected the rear loom of the golf(Corrado) from the F/Box, which has 3 multiconnectors, things like the interior light and central locking, which have there own connector, swapped out the rest of the golf loom including Fuse box, plugged them back in, the engine fired up first time!!! Then I just cut and soldered the Headlight, indicators and fog light connectors back on, everything else should connect straight up!
(At this point, I should mention that I don't have ABS and don't know anything about it, I've just got a few connector hanging around the engine bay, but assume these will conenct straight up too!?!?!?)
Also just remembered, but the ECU in the Corrado sits in the center of the scuttle pannel, where as the Golf Loom is made to position the ECU on the drivers side. This may interfear with the Wiper motor, although you may be able to get round this, I managed to drag mine through the bulk head and squash it behind the dash, where the heater matrix is on my Mk2.
This also means that the wiper motor connector might not reach, just needs extending!!
Good luck, post any questions and I'll try to help if I can!!!!!
Gav