BMW 6 Series 640i, 650i, Alpina B6 & More

The 640i is the six-cylinder side of the lineup. Depending on the era, the badge appears on a coupe, convertible, Gran Coupe, or Gran Turismo. These versions emphasize smooth turbo power and touring comfort rather than the stronger V8 thrust of a 650i.

The 650i identifies the V8-powered mainstream model. Across its different body styles, it pairs a twin-turbo 4.4-liter V8 with richer equipment than the 640i, including Harman Kardon audio on later cars and Nappa leather in later Gran Coupes.

The engine is the main difference. A 640i uses a turbocharged 3.0-liter six-cylinder, while a 650i uses a twin-turbo 4.4-liter V8 for stronger, more effortless acceleration. Later 650i models also bring richer cabin equipment, including upgraded audio.

The Gran Coupe is lower and sleeker, with four doors and a conventional trunk. The Gran Turismo is taller and more practical, with a raised seating position, more rear-seat room, and a hatchback cargo area. In the later lineup, the Gran Turismo is a 640i xDrive.

The drivetrain separates them in later Gran Coupe lineups. The 640i Gran sends power to the rear wheels, while the 640i Gran xDrive uses all-wheel drive. Both retain the turbocharged six-cylinder engine, eight-speed automatic, low four-door shape, and luxury-focused cabin.

The 650i Gran is rear-wheel drive, while the 650i Gran xDrive is all-wheel drive. In later lineups, both share the twin-turbo V8, eight-speed automatic, Nappa leather, Harman Kardon audio, and the same low Gran Coupe body.

It means all-wheel drive. A 640i xDrive Convertible keeps the regular 640i Convertible’s turbocharged six-cylinder, soft top, heated front seats, and touring-focused character, but sends power through all four wheels for extra traction.

The 650i Convertible brings a twin-turbo V8 and, on later models, Harman Kardon audio. The 640i Convertible uses a lighter, smoother turbocharged six-cylinder. Both are soft-top luxury cruisers, and both appear in rear- or all-wheel-drive form in parts of the used lineup.

The 640i xDrive Gran Turismo is the practical choice in the later lineup. It combines all-wheel drive with a hatchback cargo area, power liftgate, panoramic moonroof, raised seating position, and more generous rear-seat space than the low Gran Coupe.

A 640i Gran Coupe is the balanced pick for shoppers drawn to the low four-door shape. It provides smooth six-cylinder power, heated multi-contour front seats, navigation, and upscale cabin materials without moving to the V8-powered 650i.

The ALPINA B6 is the rarer, more specialized performance flagship. It uses an ALPINA-tuned twin-turbo V8, all-wheel drive, a tuned eight-speed automatic, adaptive suspension, distinctive details, and a hand-finished cabin. Its character favors effortless speed and comfort over track-focused harshness.

It is a limited-run 2014 650i Convertible built as a factory appearance and luxury showcase, not a separate powertrain. It combines the twin-turbo V8 with the M Sport Package, head-up display, ventilated multi-contour front seats, Nappa leather, and a digital instrument cluster.

In these trim names, “Gran” usually points to the four-door Gran Coupe. “Gran Turismo” is a different body with a taller roof and hatchback cargo opening. On used listings, check the full body name rather than assuming every model with “Gran” has the same shape.

Yes. Apple CarPlay compatibility became standard across the U.S. 6 Series lineup for 2019. Earlier examples should not be assumed to have it based only on the trim badge because standard cabin technology changed during the model’s run.