The Mercedes GLK 350 CGI 306hp (X204 - 2010 ->) produces 306bhp and 370Nm in standard form. Our Stage 1 ECU tuning file raises output to 326bhp and 400Nm, a gain of 20bhp and 30Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.