need a bit mroe info is it 1.8 driver, 1.8 8v gti, 16v gti etc? i say this as you can get drivers for a lot less miles and gti's tend to be used properly if you get my drift

! i'd be looking at bodywork if you're keeping it for a while, if thats sound mechanicals and engines are straight forward if yuo dont mind getting down and dirty! Good body work also means care has been taken to maintain it so this may also reflect the mechanicals.
16v gti's tend to be 120k - 150k average?
8v gtis vary every once in a while i see a low miler and high miler like 200k +

1.8 drivers 100-120k??
just rough guide