The Chevrolet SSR 5.3 V8 305hp (2003 - 2006) produces 305bhp and 449Nm in standard form. Our Stage 1 ECU tuning file raises output to 325bhp and 470Nm, a gain of 20bhp and 21Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.