Japan_Freak, whats it like driving a Skyline GTR34, wish i had one for a project car. I got the next best thing Twin-turbo 240sx engine swaped into a 1990 Honda Accord, you can read about it in the previos pages of this topic. Have you done any mods to your beast? If so reply.
DemonZX, The RB26DETT swap into a 300 z, would be challenging but fun, I am not sure of myself but I do believe that you have to install a new Wire/Connector set or multiple. There will be a lot of body work, because the two engines don't have the same mounting spots, that's not too bad, I had to massage my accord to match the mounting.
I agree w/ hdtboy(

) the RB is a lot taller than the Z, but you could cure that with a hood scoop or something of the sort.
Gonthrax is right the 2JZ-GTE is bascially the same engine, specs wize they are according to turbo magazine.
Demon ZX, It would be worth it to wait and purchase the RB26, there is a company out of a little town in Maryland right on the ocean that specializes in importing Jap spec Nissans, they have accounts with motorex, you could get a Skyline GTR 34, V-spec II for about $105,000 so I am not sure how much it would cost just engine only. Go to
http://www.motorex.com/usa and they can set you up with someone.
Take it easy gents, and happy huntin'