The Mercedes-Benz C-Class models really aren't very green, if you judge it based on fuel economy and carbon footprint, as most of the energy used over the lifetime of the vehicle concerns tailpipe emissions. Base C300 models are the most fuel-stingy, but even their 18 mpg city, 26 highway ratings are nothing to brag about. Ratings range down to 17/24 for the C350 and C350 4Matic models, and the high-performance C63 AMG is the environmental black sheep of the family, at 13/19.
Mercedes-Benz has been offering a turbo-diesel V-6 in the E-Class, called the E350 Bluetec, and even this model gets 22/33. But thus far the automaker hasn't offered any fuel-efficient alternative for the C-Class in the U.S.
That's bound to change, though. If you like the C-Class package but aren't a fan of the unimpressive fuel economy, you might want to hold off until later this year, when the 2012 model will get a new 1.8-liter four-cylinder engine—and an EPA highway rating estimated at around 30 mpg.
C300 and C350 models aren't particularly green, and while the C63 AMG is an enthusiast status symbol, it could be embarrassing if you have environmentally conscious friends.