The diesel’s stronger torque not only enhances the driving experience but has the performance to get the best of the 6 GT’s not inconsiderable weight. It can also be pretty frugal when not on ...

The 630i GT is claimed to return 43.4mpg with emissions of 148g/km while the 640i xDrive comes in at 35.3mpg and 183g/km. Unsurprisingly it’s the diesel that should be the economy champion with ...