Chevrolet and Pontiac-GMC announced a $1000 bonus cash incentive that is incremental to all other eligible incentives. This offer is good towards the purchase or lease of eligible new and unused 2003 Chevrolet Silverado and GMC Sierra full size pick-up models equipped with the Duramax diesel engine (PRO LB7) and Allison 5-speed automatic transmission (RPO M74), delivered from July 8, 2003 through September 30, 2003.