The BMW X6 3.5i 306hp (E71 - 2008 - 2014) produces 306bhp and 400Nm in standard form. Our Stage 1 ECU tuning file raises output to 370bhp and 520Nm, a gain of 64bhp and 120Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.