The Audi S8 4.0 TFSI 520hp (2012 - 2018) produces 520bhp and 650Nm in standard form. Our Stage 1 ECU tuning file raises output to 700bhp and 900Nm, a gain of 180bhp and 250Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.