The BMW 5 Series 525 TDS 143hp (E39 - 1995 - 2003) produces 143bhp and 280Nm in standard form. Our Stage 1 ECU tuning file raises output to 172bhp and 350Nm, a gain of 29bhp and 70Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.