What should I look for in a used BMW 6 Series coupe?
History and service records must be impeccable to preserve the car's resale value. But, high mileage isn't too much of an obstacle, provided it's all accounted for, and you are able to see garage receipts to back what the service records show.
Extras such as an information system that projects into the driver's line of sight are desirable, so long as you don't pay more than a fraction of what they originally cost.
Above all, check that the iDrive system works correctly, because some are known to behave erratically. Finally, light-coloured leather trim marks easily and shows dirt, and is best avoided if you regularly carry children or pets.