The Mercedes GL 450 - 340hp (X164 - 2006 - 2012) produces 340bhp and 460Nm in standard form. Our Stage 1 ECU tuning file raises output to 355bhp and 485Nm, a gain of 15bhp and 25Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.