The BMW X5 4.4i 320hp (E53 - 2000 - 2007) produces 320bhp and 440Nm in standard form. Our Stage 1 ECU tuning file raises output to 335bhp and 460Nm, a gain of 15bhp and 20Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.