[turbo23dog]

I heard that the on/off feature was somthing that came in later model years. I have PSE on my 2000 S and there is no switch to turn it on or off but, as already mentioned, there is a hack to make it be on all the time.

Mine works by an automatic vacuum control that opens valves to make the exhaust straight through after ~3500rpm. Its a real symhpony when open and quiet as a church mouse under light throttle at highway speeds - no drone. Best of all worlds.