Excellent choice
I'd say go for a very good condition series 2-3 rather than an R34 in average/poor condition.
You'll be able to find something good for $30-$35,000 and add a few k extra if need be (i always allow a little more cash).
I'd recommend a GTR with some minor mods. A clean, well-kept example with intake+exhaust+coilovers is a great buy with the little bits already sorted. My car came like that, and the engine was stock, so i knew it hadn't been pushed too hard.
All the best mate.