well as usual Sewid has very sound advice. to be honest the type you buy (32vs33) is no where near as important as the particular car you buy. there are stunning, mint condition 32 GTRs out there, and there are thrashed, crashed dodgey 33s out there. same works in reversve too.
for $30K you should be able to find a nice condition (either very low km, or restored/modified) R32 GTR, possibly even a Vspec or VspecII, or you can find a nice, stock 33 GTR.
anyone who owns a 33 is going to tell you 33 is the best. everyone who owns a 32 is going to tell you 32 is the best. I have owned both 32 and 33 GTR at the same time, and all I can tell you is that they are 'different' try some of each for yourself.