Damm! You beat me to it.
This was going to be my next project after completing the Supra that I am now working on. Doing the same with that-converting a Studio 27 2001 JGTC version to the 2003 spec car, I'll start a progress thread soon on this.
Back to the NSX though, I was planning on building the Mobil 1 Tamiya version and blending in some parts from one of Fujimi's updated kits e.g. headlights, front bumper, rear lights.
One question: does the Tamiya version have a large square cut out in the back window for the air scoop?
I shall be watching your progress with much interest on this one. Good Luck
Steve