I was just watching the Car and Driver video of a yellow 2001 nsx and I heard when the guy revs the engine, the engine makes a very mechanical sound. I have a 93nsx with the stock exhaust and mine does not make such a mechanical sound even when I rev it stand-still. Is this mechanical sound from the unrestricted header that the 2001 has or the new exhaust system from 97+ models. I'd really like to know. what do you think guys? What do I have to do to get this mechanical note? change exhaust or headers? thanks!