+1 on the n/a.
have one as i couldnt afford a 1.8t.
was the same to insure as a 2.0.
about the same price to buy.
same mpg pretty much.
same tax.
15 bhp ish more. doesent seem much but every little helps and ide certainly have it over the 2.slow anyday. also it doesent drink oil like the 2.0.
if your determend for the 2.0 though, usual stuff with the golfs are,
rear windscreen washer leaking
the water from the washer breaking the boot lock and seising it up/breaking the solenoid valve.
rear windscreen de-mister.
thats all i can think of off the top of my head
engine wise, same as most cars really so give it a good looking over, have a good look at the service history, give it a little test drive (both at normal driving and then give it a quick ragging) and have a look at the over all body work, see if all pannels line up ect as this can give you a idea if its been in a crash as im sure you know.