Might be Buying a New Car....need some advice.

I'm thinking of buying a new car, one that's more worthwhile to do some fun stuff to. I'm really looking for a 16V GLI or GTI with low mileage no rust. Does anybody have some advice on how to find one, other than the usual. Once I have found one what are some things that I should really watch out for?
If you know anyone that is selling a Golf or jetta with low mileage and no rust in Ontario please post. Although I'd love a 16V I'm having a hard time finding one, so I'll probably end up settling for anything rust free.
Thanks!
LBJ