Did Honda develop the supercharger in-house? When I visited Comptech in California in the summer of 1996, I heard a very nice sounding NSX being tested on a dynamometer. Comptech told me they were testing the supercharger kit Honda had hired them to develop.
Edit: When ordering an NSX at US Acura dealerships, you could then order a Comptech supercharger as a dealer installed accessory. It's too bad the 280 PS limit was in effect in Japan basically throughout the NSX's lifespan!