RENNtech EVM | Exhaust Valve Module | C-Class Pre-FaceLift MY2015-18RENNtech Exhaust Valve Module Permanently Open Exhaust Flaps. 205 C Class AMG Models Pre FaceLift MY2015 18 EVM Exhaust Valve Module (Remote Controlled) NOT SO FUN FACT: If your Mercedes AMG is equipped with factory exhaust valves, with or without a center console button to open or close them, factory settings do NOT allow the flaps to fully open unless certain speed and or RPM have been reached. For example, while cruising the exhaust flaps will