On my way there :-D sort of,
Combining an 89 Carat with a 91 Eco-Diesel, left me with a 1.6TD Jetta with power windows, sunroof, rear disc brakes, central locks, ski bag (instead of a cup holder, BUT I DON'T SKI!) Aktiv audio, power heated mirrors and what else.... oh Fuba Antenna
I put GLI front brakes on it when I had the suspension done.
General cost so far...
1989 Carat Free!
1991 Eco-Diesel $500.00
Cost two swap (fluids, hoses, belts, etc) ~$360.00
Suspension, Brakes, New tires ~$2800.00, (~$1000.00 was Labor)
I still have lots to do like, swapping in some MkIII Leather heated seats but, even now, it's the best car I have EVER owned.
You should consider going MkII, easy to add your own options.