Despite its size and heft, the M6 convertible is a rocket. Credit goes to the 7-speed automated-manual transmission. It fires off lightning-fast shifts regardless of whether the transmission is set in fully automatic mode or if the driver changes gears manually. No M6 coupes have been made available for evaluation.
Sports-car firm on the standard 19-inch wheels, yet the M6 retains a surprising degree of compliance in everyday commuting. We observed only the faintest hint of cowl shake over bumps, which is a testament to the car’s rigid body structure. No opportunity to drive an M6 with the optional 20-inch rims.
The M6 feels like a smaller car than it is, with outstanding steering, minimal body lean in fast turns, and anchor-like brakes. It might be one of the most agile of the “grand-touring” premium sporty cars, but it can’t quite match the similarly priced Porsche 911 for overall capability.
As you would expect from a BMW, the engine produces a refined, muscular growl during acceleration while being nearly silent at cruise. The wide tires drone on coarse surfaces, a condition exacerbated because of the convertible body style. Most other noise levels are on par with other high-end grand touring cars.
While the iDrive control layout is largely unchanged for 2013, BMW is giving its underlying hardware a boost. The result is a system that responds much more quickly to user input. Climate controls remain mostly separate from iDrive, which we appreciate. The large 10-inch screen is very clear and doesn’t distract while driving. The navigation system still relies on cryptic symbols, which complicates its use, but the screen can be split to show clear guidance on one side, which helps.
The M6’s standard carbon-fiber trim is extremely classy. You can get wood for no extra cost, but its appearance clashes with the car’s high-performance nature. We wouldn’t recommend it.
The M6’s sport front bucket seats provide welcome support for spirited driving. Entry and exit are coupe-typical, with long doors being a parking-lot nuisance. Visibility is poor with the convertible top up. We highly recommend the optional blind-spot alert, though at these prices, this feature really should be standard.
Rear seating is for 2, at least in theory. Headroom is scant, and legroom is virtually non-existent. If you must put someone in the back, put the convertible top down, it makes entry and exit much simpler.
Cargo volume is what you would expect from a convertible this size. A couple golf bags or a weekend’s worth of soft luggage will fit without issue. Meager interior storage includes a small glovebox, center console, and door pockets. The available smartphone integration includes a dock that occupies most of the space inside the center console. The dock is sized in just such a way that Apple iPhone owners must remove any extra case before connecting it.
BMW 6-Series Gran Coupe:
Despite being the least-powerful model, the 640i Gran Coupe with its 6-cylinder engine is plenty fast. BMW claims this car will do 0-60 mph in 5.4 seconds, and it feels about that quick based on our seat-of-the-pants impression. It’s so perky and smooth, we almost question the need for the V8-powered 650i. Note, though, getting the V8 is the only way you’d be able to order this car with all-wheel drive. The V8 boasts 130 more horsepower than the 6-cylinder, and it shows. The car jumps off the line and charges ahead with gusto. BMW says 0-60 will happen in 4.5 seconds. The 6-Series Gran Coupe’s standard 8-speed automatic transmission changes gears smoothly, though it occasionally exhibited reluctance to downshift for highway passing and merging.
No opportunity to measure. EPA estimates place 6-cylinder models at 20 mpg city/30 mpg highway. V8 models are estimated at 17/25 with rear-wheel drive and 16/24 with all-wheel drive. All Gran Coupes require premium-grade gasoline.
Both of the models tested were equipped with the optional M Sport Package. It includes 19-inch wheels (18s are standard). Drivers can adjust the suspension and chassis among five modes: Eco Pro, Comfort+, Comfort, Sport, and Sport+. We didn’t notice much difference among Eco Pro, Comfort+, and Comfort; in these modes, the suspension is softer, which puts it at odds with the high-performance tires included in the M Sport Package. We found Sport to provide the best balance between comfort and handling. In this mode, the ride is firm but well-controlled. Sport+ doesn’t alter the suspension, but it dials back the antiskid system for spirited driving.
The Gran Coupe has a longer wheelbase and overall length when compared with its 2-door sibling. So while it is bigger, it doesn’t feel more cumbersome, driving like a smaller car than it really is. Steering feel is excellent, and body lean in fast turns is minimal with the suspension in Sport mode. There’s a bit more in Comfort and Comfort+, though it detracts little from the experience. The brake pedal felt slightly mushy on our 640i test car, but there were no other issues with stopping power or control. The V8 model we sampled was equipped with an auto-hold brake. When switched on, the engine shuts off at a stop and the auto-hold prevents the car from moving. The driver can release the brake pedal, and the car remains stationary until the accelerator is pressed. At that point, the engine restarts, the brakes release, and the car operates as normal.
BMW’s turbocharged 6-cylinder engine produces a classy noise during acceleration and settles down to near silence on the road. The V8 lets out a muscular growl during hard acceleration. The M Sport Package’s wide performance tires drone loudly on coarse pavement. This is the only real quietness issue. A slippery exterior shape translates into minimal wind noise.
The control scheme is standard BMW fare. The climate controls are largely separate from iDrive, while that console knob governs most audio and all navigation and related systems. It takes acclimation as performing some tasks requires drilling fairly deep into sub-menus. The navigation system itself is fairly intuitive to program, but the actual display doesn’t show many street names, which is confusing if in an unfamiliar area.
High-grade leather, contrast stitching, and soft-touch surfaces abound inside the Gran Coupe’s cabin. The M Sport Package’s unique trim is appropriately sporty, particularly the synthetic-suede headliner.
Gran Coupe’s front seats are comfortable and supportive. BMW’s “Multicontour” buckets allow for a myriad of power adjustments to suit occupants of nearly all shapes and sizes. The car’s sloping roof line and sunroof housing limit headroom unless you put the seats in their lowest position. The 4-door’s smaller doors make it easier to enter and exit the car in tight spots, but you still need to duck a bit so as not to bump your head.
Despite a substantial increase in wheelbase over its 2-door counterpart, the Gran Coupe doesn’t have much more rear-seat space than a compact car. Legroom is just OK behind front-seat occupants who are about 5’8″-5’10”. The sloping roof line limits headroom. BMW offers a center-seating position on this car, but anyone who has the misfortune of sitting there will have to straddle the driveline hump as well as the center console.
The trunk is fairly deep but not very tall, so care should be taken when loading bulky cargo. Split-folding rear seat backs are standard. Interior storage consists of a decently sized center console and door pockets. The glovebox has a fair amount of space once you remove the owner’s manual.