I have an E220 CDI Bluefficiency and it's good. One oddity is that it's not very economical in cold weather, and very economical in warm weather. This is on long (1.5 hour) journeys, and I am fully versed in all the usual discussion about the performance of diesels in the cold. However... I discovered that my heated mirrors are on nearly all the time. Even with the switch off. It transpires that if the outside temperature drops below 15°C then the mirrors heat up the passing atmosphere until the temperature rises all the way up to 18°C at which point they turn off. For a car that claims to have LED rear lights to save energy it seems odd to have two dirty great electric heater elements pointlessly switched on in the airflow. But MBUK have confirmed that this is how it's meant to work. The question is: car someone with the MB magic interface turn this "feature" off, so I can just turn the mirrors on and off with the switch? One element has already burnt out, and I guess more failures are to follow. Thanks..