personally i wouldn't buy one that high without service history. the small block vw engines often throw headgaskets at about the 80k mark, so by now it could have had 2 if not more!! I'd want to see regular stamps, bills and a lot of old mot's!! Going by how our parade looks after bloody 76k i'd hate to imagine how rotten it is!
I would pay about 1500 for a high mileage g40, or for a v. low mileage gt but then again 500 isn't bad, if only for the cylinder head and fuel injection system, which is a good upgrade for a basic polo of any engine size.
but then again if it's good go for it, as good 1.4 engines come up all the time, and you can just swap the engines and parts lol.
Jon.