GM announced today that it will now be offering a 5 Year or 100,000 miles Powertrain Warranty across its entire line of 2007 models including Cadillac, Hummer, Saab, GMC, Pontiac, Chevrolet and Buick. The warranty is also active for anyone who has already purchased a 2007 model vehicle. The news comes just two months after Ford announced its 5 year or 60,000 miles warranty.