agree with the post above! buy a mk3 and start plannin it all out.
can do alot of the main stuff yourself, dont expect it to be a half hour job though, loads and loads of complications can occur... i helped with a turbo diesel transplant for a caddy, however that took all of about 4hours(had to wait for the engine crane) but i hear the VR6 conversion can take the monkey.
well worth it by all means though!