There are four TwinPower Turbo engine options: the 18d, 20d and 25d diesels, plus a petrol 20i. All benefit from variable turbine geometry, which improves power, torque, response and fuel economy. The option of eight-speed transmission - standard on xDrive 20i and xDrive 25d – smooths gear changes and further reduces fuel consumption. Fuel economy is highest in the sDrive 18d, which emits just 114g/km of CO2 and returns up to 68.9mpg. Meanwhile, ECO PRO mode works to maximise the efficiency of everything about the car, from your driving to the climate control, and can save up to 20 percent on fuel.