The switch that opens up the 2nd pipe is purely mechanical, right? Then I think it's the best muffler out there since it is quiet and not restrictive at all.

 

It's not VTEC. That's all honda and all valvetrain related. The 5th gen muffler doesnt even have a "switch" in it really. When the RPMs get to a certain point, there is enough force for the exhaust gasses to push open a vlave that opens up the other muffler chambers. That's all. Nothing too fancy.