The Mercedes CLS 300d (2.0D) 245hp (C257 - 2018 - 2020) produces 245bhp and 500Nm in standard form. Our Stage 1 ECU tuning file raises output to 270bhp and 560Nm, a gain of 25bhp and 60Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.