This plug-in hybrid combines a 3.0-litre V6 with a big battery pack and an electric motor. Although the petrol engine isn’t quite as smooth as the S 450 and S 500’s straight-six, its near-silent electric-only running is a perfect fit for a luxury car. Range in the real world is around 20 miles with gentle stop start driving its preferred habitat. When both power sources contribute power, it’s rather quick, too.