It deffinately won't cost anywhere near 10 grand for any motor swap if you're planning on doing it yourself, especially a VG30 swap, that's like the cheapest Nissan motor you can buy. A VG30 is a whole lot better motor when it comes to performance then the RB series motors. More displacement, high compression, etc. You can pull like 450h.p. out of a VG motor without even replacing internals.
http://jspecauto.com/catalog_p...id=49
2 grand for the motor and transmission. Shipping is between $200-$375 depending on the motor. I'm pretty sure you can swap it into a 240sx, I know for sure that the VG30DE can be swapped into the 240sx, but I don't know for for a fact that you can swap the VG30DETT.