The Audi RS4 4.2 FSI 450hp (B8 - 2012 - 2017) produces 450bhp and 430Nm in standard form. Our Stage 1 ECU tuning file raises output to 475bhp and 460Nm, a gain of 25bhp and 30Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.