Most of the BMW 6-Series lineup isn't seeking recognition as a purebred sports car, or record lap times; as a rather large, hefty touring Coupe or Convertible, its specialty is devouring long stretches of interstate--or autobahn--while staying limber enough to take on mountain roads without breaking a sweat.
Throughout the 6-Series lineup, and whether you're talking Coupe or Convertible, there are two models: 640i and 650i. At a time when BMW names correspond to virtual, not actual engine size, and turbochargers are part and parcel to the lineup, the 640i uses a 3.0-liter TwinPower turbocharged six-cylinder engine rated at 315 horsepower, while the 650i gets a 4.4-liter twin-turbocharged V-8 engine rated at 400 horsepower.
Both engines are willing performers, but we do tend to think that the larger, more laid-back character of the V-8, and its easy, smooth power, better suits the 6-Series' own personality. Handling is confident, and the 6-Series models track well, and while they steer and maneuver as lighter cars we do wish that the steering had a more natural feel, or some feedback. These are cars that can cruise effortlessly at well above 100 mph, so you'll need to take some extra measures if you're already a chronic speeder.
In either the 640i or 650i models, you get an eight-speed automatic transmission that shifts smoothly and seamlessly, and rises to the task of more aggressive driving surprisingly well. A six-speed manual transmission is essentially a no-cost option, offered only on rear-wheel-drive V-8 models. You can also get xDrive (all-wheel drive) on 650i Coupe or Convertible models (only with automatic), making them one of the few drop-tops with AWD.
All of these models are highly adjustable and customizable, through a system called Driving Dynamics Control. Through Comfort, Sport, and Sport+ modes available at the press of a console-mounted button, you can change throttle response, transmission behavior, and suspension settings, to best suit the type of road you're on, or the kind of company you have in the passenger seat.
New for 2013—actually introduced as a Convertible late in the 2012 model year, but now new as a Coupe—is the new-generation super-performance M6. Just as the latest M5, it dumps the thirsty former V-10 in favor of a 560-hp BMW M twin-turbo V-8, mated to a special seven-speed M Double Clutch gearbox that offers exceptionally fast shifts. That's matched with an M specific chassis, upgraded brakes, special sport seats, and extensive M Drive controls over suspension, steering, powertrain, and stability controls. It even includes two customizable setting buttons to quickly dial in a different character for a certain kind of driving.