The golfs were GTI's on MK1's, GTI's, G60's on Mk2's. For the MK3 Polo's there were G40's, and GT's. The G40/60's are supercharged and generally the quicker of the bunch although I like a good MK1 1.6 8v gti myself (naturally aspirated)- just got to love the retro :P
Looks like a nice car you've got there man the GT's are really good value now just watch for the rust and headgasket. How many miles does it have? I'm guessing about 110,000.
They can look delicious too with only a litlew bit of work, give yours a good polish and it will look 100 times better just with that, also some new number plates maybe as your's are a little faded.
All in all nice one mate, hope the insurance isn't too much of a killer. Now, for some inspiration...