Wake up the full power and sound of your twin-turbo V8 with the Untd. Performance Catless Downpipe for the Mercedes-Benz GLC63 AMG. Designed for the M177 4.0L engine, this no-compromise performance upgrade removes the factory catalytic converters, significantly improving exhaust flow, turbo efficiency, and overall engine response—while delivering the raw, aggressive exhaust note that the factory setup hides.