My friend bought one of the Grip DVD's and they showed Apexi's new exhaust series, the PS Revolution Series. So far I can't find anywhere in the US that sells it but they do have it at http://www.takakaira.com/performance/main.html with a pretty informative write-up on how it works. (Just click on APEX, then Exhaust, the PS Revolution) There is even a dyno graph of it on the FD. What do you think of it? It sure as hell would quiet down some of our exhausts while just cruising around town.

 

Very interesting. Gordon Monsen had a SARD exhaust that has a similar feature. The valve made a really cheap rattling noise at low rpm. I think it's a great concept though. Hopefully the apexi model will sound better.

 

In the Grip video they showed it on a s14 or s15 (forget which) and revved it and it sounded nice. transition sound was great and much louder then when closed.