RENNtech EVM | Exhaust Valve Module | 463 - G 63 AMG MY2019+ | G550 MY2018+RENNtech Exhaust Valve Module Permanently Open Exhaust Flaps. 463 G 63 AMG and G550 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 never fully open! THE EVM