I think alot of people would recommend you look at private buys as well.. You will find that most dealerships - especially Parramatta Rd have quite a high markup on cars.. e.g. the equivilant R33 to mine - 40th Annv will cost you up to $26,000+ in a dealership, when privately you would be looking at $22,000..
well - it's up to you.. check him out and see what you think - all dealers MUST offer you 3 months warranty, this can be a good thing, personally if there is something overly wrong with your car in the first 3 months i'd be a bit worried..
Anyways - good luck