You are not correct in comparing the systems as you do.
There are basically 2 systems, sport and prestige, the difference being the diameter of the front straight through silencer. Sport being the louder one obviously.
Both systems has the option of adding a powervalve to the rear silencer enabling it to run straight through the rear silencer via a 3" tube when the required boost is achieved. Below the required boost it goes via a 2,75" tube through the dampening part of the silencer/muffler.
So a sport with a pw above the required boost will be louder than a sport without a pw. And the same goes for the 2 prestige versions. My guess is a prestige wirh PW is similar to the sport without PW.
I hope this makes sense?