Mercedes-Benz appears set to fit a diesel engine into the SLK roadster when the next redesign appears in early 2010, according to AutoblogGreen. The company's recently-introduced, twin-turbo 2.2L four will be the likely culprit.

The report said that in dual turbo guise, the engine puts out 204 hp and a stump-pulling 369 lb-ft of torque, which should be enough to propel the SLK square into sports car territory. "The C250 sedan that just launched in Europe with the same engine gets a combined rating of 45.3 mpg (U.S.) and should be able to achieve real world mileage in the upper 30s with ease," according to the report.