The Buick Rendezvous 3.5 V6 198hp (2003 - 2005) produces 198bhp and 289Nm in standard form. Our Stage 1 ECU tuning file raises output to 215bhp and 310Nm, a gain of 17bhp and 21Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.