Hi FastCanuck, wrxhoon and blitz know what they are talking about.
I can see where you are coming from though, you are hoping to pick up a car that would normally private sell for about 35k at a trade in price of about 25-28k.... It possible but you may be waiting a while since no one wants to let thier GTR go that cheap. You are right demand has dropped for the skylines in general, due to a lot of people importing them and then deciding they don't want them 6 months later so now the market is flooded...
Unfortunatly you will have more of a chance of picking up a Lemon for that price than a good one... We've seen it with the R32 GTR's, lots of guys imported them under the 15 year rule, got them cheap and a lot of them ended up with a stuffed engine not long after they bought them.
I think the best deal i've seen for an R33 GTR which is a nice/good one is the one that GTRgeoff picked up for about 30k... that got snapped up very quickly because it was that cheap and was in pretty good condition...
If you hang out long enough you may find something close to what you're after, but don't expect it to be anytime soon...
GoodLuck.