Comptech makes the only NSX body kit readily available in the US. The others are just skirt/wing bolt-on bits; hardly true body kits.
There are people importing the JDM kits, but their reliability varies wildly and people regularly kiss their deposits goodbye. Also, the quality of the JDM kits is all over the place. Some are nice, but many are really poorly built. And, the kits syled for that market tend to be really cartoony or 'boy-racer' looking.
IMHO, the Comptech kit is the only way to go. I have it on my car and when it is in Bob Norwood's shop, people regularly walk right past the F-40s and F-50s and say "wow! what the hell is this?" I really amuses Norwood, as he is a die-hard Ferrari tuner.
By the way, if you ever need really custom turbo or fuel system work, he is the man. He took a couple of his cars and a couple of customer cars to the salt flats a few weeks ago and set FIVE new land speed records. Already had several. One of them eclipsed the old record by over 50 mph!!!!! He is famous in the Ferrari world for building crazy fast (600 hp+) 328s and (1200+ hp) Testarossas. The guys who founded ID (Doom/Quake) keep him really busy building toys like twin-turbo methanol fueled F50s. Just built a 650 hp 1.4 L MR2. Also, he is a nice guy.