The Mercedes C 300de 306hp (W205 - 2018 - 2021) produces 306bhp and 700Nm in standard form. Our Stage 1 ECU tuning file raises output to 335bhp and 760Nm, a gain of 29bhp and 60Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.