Akrapovic Sound Kit (Exclude M5 CS) - BMW / F90 / M5P HF1132 The optional Akrapovi Sound Kit enables owners of selected Akrapovi car exhausts to control the sound of the system from the cockpit of their machine. Using Akrapovi technology, drivers can easily switch between the quiet mode and a sportier sound. With the use of a receiver (already included in evolution system) to drive the actuators that open or close the valves at the end of the exhaust system, drivers can use the Sound Remote Controller