Why are R34's so expensive?

[predator]

I think part of it would be the fact that there are no new turbo charged vehicles getting released in Japan to fill the void.

None of the new n/a models are as popular as some of the older models, and there is nothing to fill that gap, making the older models more popular than they otherwise would have otherwise had been.. those who want something with a large amount of tuning potential that isn't too old.

I would say increased demand from the rest of the world may also add to this (some countries only able to import cars less than 10 years old, etc).