i reckon buying cars advertised on forums is not really a good idea, cars are pretty much overpriced because there are alot of enthisiats that think that their car is worth alot more than what they really are, i mean common its late 80's to early 90s car. Just browse them to get a fair idea.
I like to think and im sure alot of people agree that R32s and R33a are not worth alot nowadays.
I bought my R33 GTST series 2 with 76 thousand genuine kms and a 16 month mechanical warranty for 10 Thousand. Off carsguide. your best bet is sites like this, carsales, drive etc etc
Trust me, youl find the right one, and if you call up thinking you found the perfect car, then the owner tells you its sold, dont giveup, youl find a better one at a better price!
Good luck mate.