Upon its introduction in the U.S., the 2007 Mercedes-Benz S-Class will be offered as either a S500 or S600. The S500 model will feature a 382-horsepower, 32-valve V8 engine with variable valve timing. S600 models will feature a twelve-cylinder engine that promises more than 500 horsepower. In comparison, the 2005 S-Class S500 offers 302 horsepower and the 2005 S600 pumps out 493 horsepower.