The Mercedes GLK 350 CDI 231hp (X204 - 2008 - 2010) produces 231bhp and 540Nm in standard form. Our Stage 1 ECU tuning file raises output to 260bhp and 600Nm, a gain of 29bhp and 60Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.