I just went through this, you can get a cd009(a) or jk4## transmission for around $900. The whole adapter kit from collins is about $900. If you don't have access to a CNC machine you will have to pay to have the bell housing milled, we will call it $250 for this, other small parts we will say $200. That's $2,250 for a z33/z34 trans.
I just bought a brand new gts-t 5 speed (no miles) from RHDJapan for $1,950 (including shipping and processing fees).
The aussie guys say that the 5 speed is pretty stout, and there is a strong resell market for the five speed (at least in the US). I eventually chose the 5 speed because I know it will just work with my RB. I don't have to worry about something wrong with the milling or the correct clutch/hardware.
I hope this helps. If you have any questions about using RHDJapan I am more than willing to help answer.