The new SLK 250 CDI makes use of the Stuttgart-based automaker’s 2.1-liter turbocharged four-cylinder diesel engine delivering 204-horses (150kW) and a hefty 500Nm (368.8 lb-ft) of peak torque.

As for the GLK 220 CDI BlueEFFICIENCY, it is also fitted with a four-cylinder diesel engine able to develop 170 hp and consumes only between 6.0 and 6.4 l/100 km (between 39.2 and 36.8 mpg).

C 250 CDI BlueEFFICIENCY is a mere 4.6 litres per 100 kilometres, and 5.1 litres per 100 kilometres according to the present NEDC method. This represents an improvement of around 30 percent ...