Don't think you can get a Mk2 TDI, it will have been the TD producing about 75 bhp, certainly not the TDI engine as fitted to Mk3 Golfs/Audi's etc. Probably would have been badged a CL-TD as well.
As an alternative to the Mk3 GTI, I would look at the Mk3 TDI. Performance won't be far short of the GTI when you are moving and overtaking as the torque is huge. Disregard the 0-60 times as they are worthless on the road, but instead look at the 30-50/50-70 times as they are more real life.
OK, the suspension will be a bit softer, but that can be fixed with a new set. The only thing that yo might find is that they will be high mileage examples and te price will probably still be high compared to the GTI of a similar age/mileage.
Serviceing costs will be higher as well, as the oil/filter will need to be changed more frequently, but you have to offset this against the fuel economy/insurace etc that you will be paying.
HTH,
John.