Im Tom's son, i did this conversion. took me about 24 hours total, and ive never touched an NSX before. ive swapped alot of newer subarus from automatic to manual, and this swap was quite a bit easier then those.
parts i used:
trans+clutch (obviously)
left and rear mounts
intermediate shaft
shifter with aluminum mount that secures it to the body
shift cables
brake pedal
clutch pedal assembly, master and slave cyl.
i made a hardline for the clutch out of brake line tubing, ran it under the car with the a/c lines and coolant pipes. i chose to swap just the brake pedal out instead of the gas/brake assembly. the pedal was the only difference and theres not much room under the dash to pull the whole assembly out. electrically, i unsoldered the harness from the PRNDL switch on the auto shifter, and ran my reverse light switch, clutch switch to start, and clutch switch for cruise cancel to the pigtail and soldered everything and heatshrinked it. plugged pigtail back into the main harness. clutch pedal was probably the trickiest part to install due to the lack of space under the dash. i used a piece of matte black vinyl to cover the PRND christmas tree on the dash, due to a manual cluster being very expensive.
the car drives exactly like factory. no warning lights on for anything, trac/abs/cruise all still works like stock. all the parts for this job cost less the 4k, including a manual steering rack i havent installed yet, and a spare tire due to the car not coming with one. even with the swap my dad is into this car for thousands less then it would have cost to buy a stock 5spd in the condition this one is in.
if you can change your own timing belt on a NSX, you can do this swap. its very straight forward, and the way i did the wiring made no permanent changes to the car or harness.
post swap, time to store it for the winter.