The later 2.0 16v was made eligible for ITA a few years ago but I don't know if anyone's built one. I don't think they are perfect on paper but they should be in the ballpark, assuming build quality, budget, and driving skill are comparable.

The 1.8 is listed 275 pounds lighter than the Rat motor. I've seen a couple of examples of that car and they seem to struggle. I don't know if it can actually get down to its race weight.

Under current rules, it's legal to turn an 8v or early 16v into a 2.0 if the car you end up with is exactly the same as it would have been if you'd started with a "real" 90-92 GTI (e.g., big bumpers).

Where are you located? There might be people near you who can help...

K