Jeff - Look in the tdi conversions sub forum on tdi club. There's a guy who did exactly what you're doing. A company makes an adapter plate to mate it up to a toyota tranny. That'll probly be your best bet.
With some bigger injectors, tune, bigger turbo, better intake manifold, and a cam (if you really feel like modding), ~180whp is easily doable. And a 180hp tdi has ~325lb/ft, so it'll scoot pretty well. No head studs or anything like that are needed.
You can take a 1.6td pump, put a tdi camplate and head on it, and then you have a mechanical pump that will run the direct injection system on a tdi. But, the electronic ones drive sooooo nice when tuned so I would suggest swapping the electronics all over. Rocketchip can make the ecu happy with no cluster or key hooked up.