The BMW 3 Series M3 431hp (F3x - 2011 - 2015) produces 431bhp and 550Nm in standard form. Our Stage 1 ECU tuning file raises output to 500bhp and 650Nm, a gain of 69bhp and 100Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.