If the exhaust you are referring to is "Fujitsubo", that's what I have on my car. Absolutely love it, it's perfect. Civil enough at low RPM that I don't have to worry about pissing off the neighbors, plenty loud enough at high RPM with a wail on downshift that never fails to put a shit-eatin' grin on my face, and no drone during highway cruising. Came with the car when I bought it, props to Honcho (previous owner) for all the hard work he did researching it.
When I saw this thread pop up, I was going to reply with a link to that thread but never got back to it. Seems you had already decided on the Fujitsubo anyway. At the time Honcho bought his (he actually bought two and sold one), there were only 3 NSXs in the country with that exhaust, NSX78__, his, and the guy he sold the other one to. They're pretty rare.