The Mercedes CLS 63 AMG 557hp (C218 - 2014 - 2018) produces 557bhp and 720Nm in standard form. Our Stage 1 ECU tuning file raises output to 660bhp and 1100Nm, a gain of 103bhp and 380Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.