The GMC Sierra 6.0 V8 360hp (1999 - 2007) produces 360bhp and 525Nm in standard form. Our Stage 1 ECU tuning file raises output to 380bhp and 545Nm, a gain of 20bhp and 20Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.