The BMW 5 Series 525D 163hp (E39 - 1995 - 2003) produces 163bhp and 350Nm in standard form. Our Stage 1 ECU tuning file raises output to 195bhp and 430Nm, a gain of 32bhp and 80Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.