Hi There, welcome to the forum
I'm a relatively new GTI owner and i would recommend looking for a car with a few of the optional extras if you can, you wont regret paying extra.
I've been running the car for a month now with a mixture of driving (B-road blasts through to Motorway cruises) and i have been averaging 31mpg - which i think is great for a 200bhp hot hatch.
as mentioned, check the air con on start up. My car is a 55 reg car and there is a strange smell coming from the air con for the first 2-3 mins of it running, then it goes.
Cambelt should be done either 60k or every 4 years, which ever is first. If you are looking for a car of this kind of age, get the waterpump done at the same time to save work later on. I would advise making it part of a potential deal.
car handles and pulls well, weakest point I would say are the oem brakes.
I agree - set of EBC redstuff pads should sort it out (so i've heard...)
Hope this helps! Good luck