The Mercedes CLK 55 AMG 347hp (W208 - 1997 - 2002) produces 347bhp and 510Nm in standard form. Our Stage 1 ECU tuning file raises output to 367bhp and 535Nm, a gain of 20bhp and 25Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.