[Riker]

All the modes simply alter when the valve is open or closed.

Tour leaves the valve closed at all time outside of start-up, high RPM and high throttle input. Which means it will be open just as much as Sport/Track mode on the track. If you go WOT, Tour/Sport/Track are all the same loudness. The valve simply opens to the "loud/less restrictive" exhaust path. Closed makes the exhaust go the "quiet/more restrictive" path.

Sport/Track modes leaves the valve open in almost all circumstances outside of steady state speed above 10-15 mph with low rpm/throttle (avoids drone). Track opens up with even less RPM and throttle than Sport. But as I mentioned, when you are going WOT at the track, Tour will not make a difference outside of some braking zones where you are off throttle. But that doesn't matter at all since it is about peak loudness which is when you are WOT.

Stealth keeps them closed no matter what. The question is if it is damaging, not just lower performance.