Akrapovic Sound Kit for Porsche Cayenne (536 - 9YA)OP Optional partFurther control over the sound of the Evolution Line (Titanium) exhaust system can be achieved by installing the optional Akrapovi Sound Kit. This gives the occupants of the car the option to regulate the exhaust tone by switching between the quiet mode and a sportier sound. This is facilitated through the use of a Sound Remote Controller or the smartphone app (for iOS and Android), which regulates the valves to drive the actuators