They have integrated sound control valves in the exhaust system just ahead of the mufflers on each side. They are supposed to modulate the sound in four cylinder mode to make it more pleasing to the ear. How affective they will be is probably subjective, and will cause more controversy on the forums.
These are not to be confused with the valves in the muffler outlets that come with the dual mode NPP exhaust option. With NPP you will actually have four valves; two before the mufflers and two after the mufflers. All are now electric as opposed to the vacuum operated valves used with the previous NPP option.
I’ve attached a photo to show the location of the valves.
Ed
