Codenamed W221, these 2006 S-Class test cars undergoing cold weather testing have just a smidgen of camouflage hiding a handful of details. The seventh-generation S-Class measures larger than today's version, and will offer a new lineup of engines including V-6 and V-8 offerings, and an all-new 3.0-liter V-6 diesel with over 230 horsepower, as well as a 4.0-liter V-8 diesel. Other options will likely include a 6.3-liter V-8 with 600 horsepower and a 6.5-liter twin-turbo V-12. Bells and whistles, as expected, will likely include pedestrian airbags that would eject from the grille if it senses such an impact, as well as an advanced crash avoidance system and an estimated sixteen airbags. You can get a good idea as to the new S-Class styling here, or you can wait until next fall for its official introduction, probably at the Frankfurt Motor Show.