Autos

Mercedes-Benz ML320 Bluetec

On sale: Fall, 2008

Fuel savings today, 15,000 miles: $305
Year-ago savings: $802
Difference: $497
Mileage: 24 mpg highway
Closest gas model: ML350
Mileage: 20 mpg highway

Like other diesels from Mercedes-Benz, the ML320 Bluetec will probably start from a cost disadvantage, since the company charges extra for diesel models. A $1,000 higher sticker price means it could take three years to break even, before the diesel starts saving money via better mileage. Still, the higher torque of a diesel engine has other benefits for SUV customers, such as making it easier to tow a boat or trailer, or for occasional off-road driving.