640xi

This all-wheel-drive six-cylinder variant appeared in the 6 Series lineup for the 2014 model year, when the range expanded to include xDrive versions of the Coupe and Convertible alongside the Gran Coupe. In market naming, the badge was often written with xDrive, while some databases shorten it to a single "xi" form. The model sat in the upper grand-touring end of the 6 Series family, pairing a more practical use of power with the line’s traditional emphasis on style and long-distance comfort. For 2017, the range gained the 6 Series Gran Turismo body style, and the same 640i xDrive naming carried that model into the final years of the series. The 6 Series line ended after the 2019 model year, which also marked the close of this variant’s run. This nameplate is best understood as the all-wheel-drive version of the mainstream six-cylinder 6 Series rather than a separate performance sub-brand, and it bridged several body styles during the final generation of the badge.