I have a supercharged NSX pushing 400whp and I would take a Porsche 996 twin turbo or GT2 in heartbeat for a trade....if they would let me. The NSX is a great car but it is behind the times on several items that need upgrading. Anyone has tracked their car knows that just adding a supercharger and aftercooler to an NSX isn't going to do it. You need better brakes, coilovers(noncompliance parts), and most likely a new clutch to hang with the new power.
The Porsche comes from the factory faster and due to that it has better brakes and suspenion ready to go. I don't care about the "Nobody knows the difference between a 911 C2 compared to a GT2" Since most of those people are not gearheads. I drive with Porsche guys a lot and they can do amazing stuff with those 911 turbos. I love those cars and they kicks some serious ass at the track.
I would like to know what the parts cost as well but I am sure anything for either car is still expensive.