I've did mine last year. It's a challenge if you have never done this before, but once you do it, becomes a hell of a lot easier on the opposite side. Not too mention how tight the space is behind the seats.
There are several pieces you need to remove from the interior because they're all connected. From the rear panels, side panels, all the trim long the door sills, seat belt retractor brackets and part of the rear headliner. Make sure you buy extra clips that hold the panels together. For sure you'll end up breaking a few
Here is my old thread from last year. Lots of people helped me through this task. Good luck
http://www.nsxprime.com/forums/showthread.php?t=98145