Unlike the lads above I think the price is ok. Looking at carsales the first manual non turbo is $25k with 150,000 k's on it. Though its likely to be a factory manual, it does give some food for thought. The auto R34 GT's start at 13k. So, for me, 20 is ok, but 17 - 18 would be better.
For reference, the first GTT is $30k but an auto.