The Mercedes CLS 350 CDI Bluetec 252hp (C218 - 2010 - 2014) produces 252bhp and 620Nm in standard form. Our Stage 1 ECU tuning file raises output to 300bhp and 700Nm, a gain of 48bhp and 80Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.