The Buick Lacrosse 5.3 V8 300hp (2005 - 2009) produces 300bhp and 438Nm in standard form. Our Stage 1 ECU tuning file raises output to 320bhp and 460Nm, a gain of 20bhp and 22Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.