The Mercedes CLS 500 306hp (C219 - 2004 - 2010) produces 306bhp and 460Nm in standard form. Our Stage 1 ECU tuning file raises output to 326bhp and 485Nm, a gain of 20bhp and 25Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.