The Audi A8 4.2 TDI 350hp (D4 - 2010 - 2016) produces 350bhp and 800Nm in standard form. Our Stage 1 ECU tuning file raises output to 400bhp and 950Nm, a gain of 50bhp and 150Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.