Though the 6-Series convertible shares a platform with BMW's unassuming 5-Series sedan, you'd be hard pressed to tell that by looking at its shapely exterior. Well-balanced proportions and graceful surface detailing give the convertible an understated yet subtly muscular look that will likely still look fresh 20 years down the line.
Simplicity of design and opulence of material quality are the defining characteristics of the interior. A minimalist instrument panel serves up all of the vital information the driver needs - nothing more, nothing less - while BMW's iDrive infotainment system keeps the number of secondary controls down to a manageable level.
This straightforwardness contributes greatly to ease of use and also focuses attention on the supple leather upholstery, delicate French stitching and impressive wood or aluminum trim that adorns the cabin.
Entertainment, navigation and Bluetooth functions are displayed on a 10.2-inch high-definition display and controlled by iDrive, which was much-maligned when first introduced but has since evolved into one of the more user-friendly infotainment systems on the market. iDrive also provides access to ConnectedDrive, which enables passengers to get directions with real-time traffic information, surf the internet on the go, utilize concierge services and more.
A variety of high-tech driver and safety systems are optional: Surround View parking camera system, Parking Assistant, BMW Night Vision with pedestrian recognition, a Lane Departure Warning System and Active Blind Spot Detection along with the BMW Head-Up-Display. The latest incarnation of this system projects vital information onto the windshield in full color. For audiophiles, the Bang & Olufsen High-End Surround Sound System provides what BMW describes as "a feast of aural pleasure seldom experienced inside a car."
Interior space is abundant for front-seat occupants, but a paucity of legroom and headroom mean the rear seats are best left to children. The power-operated cloth soft top takes just 19 seconds to lower or 24 seconds to raise, and either action can be performed at speeds of up to 25 mph. With the top up, there's 12.3 cubic feet of cargo space, while opening the cabin to elements requires the sacrifice of only 1.7 cubes.
Under the Hood
The 6-Series convertible is offered as the six-cylinder 640i or the eight-cylinder 650i.
The 640i features BMW's smooth single-turbo "N55″ 3.0-liter inline-six, which makes 315 horsepower and 330 lb-ft of torque. Though slightly slower than the 650i, the 640i's smaller engines equates to a lighter overall weight and slightly more nimble handling as well as an impressive fuel economy: the EPA rates the car at 21 mpg in the city and 31 mpg on the highway.
The 650i packs BMW's twin-turbocharged 4.4-liter V8 under the hood, which was upgraded for the latest model year with BMW's Valvetronic variable valve timing and lift system. This change helps the mill to crank out 445 horsepower and 480 lb-ft of torque (upgrades of 45 ponies and 30 lb-ft). Zero-to-60 mph can be achieved in under five seconds, though fuel economy drops to 15/23 mpg.
Both models shift through an eight-speed automatic transmission Available exclusively on the 650i is BMW's "xDrive" all-wheel-drive system, which adds a couple hundred pounds of agility-sapping weight but allows the big coupe to motor its way through all but the worst inclement weather.
Although the 6-Series convertible is a large and heavy machine, careful chassis tuning means that it drives like a much smaller, lighter vehicle. An optional Adaptive Drive system ratchets up the sportiness factor by using electronically adjustable dampers and stabilizers to minimize body roll. Also optional is Integral Active Steering, which adds rear-wheel steering to the mix in order to increase low-speed agility and high-speed stability.
Standard and Optional Features
The 6-Series convertible comes standard with leather upholstery, a navigation system with a 10.2-inch display, voice command functionality and 20 GB of storage space, a Wi-Fi hotspot, a wireless charger, heated front seats, dual-zone automatic climate control, dynamic cruise control, a rear-view camera, a nine-speaker, 205-watt AM/FM/CD stereo system with HD radio and a USB input, a sunroof, a proximity key, xenon headlights, LED foglights and 18-inch alloy wheels.
Highlights from the lengthy options list include the M Sport Package, which includes an aggressive body kit, Shadowline exterior trim, an M steering wheel, Alcantara headliner and 19-inch alloy wheels; the Executive Package, which brings ventilated multi-contour front seats, a head-up display, a premium sound system and concierge services; and the Lighting Package, which adds full LED lights and automatic high beams.
A newly available M Sport Edition package builds on the normal M Sport package by adding extra features at no extra cost. It decks out the interior with a Nappa leather dashboard and a head-up display. Opt for the 650i and BMW will throw in a handful of extra safety and driver assistance systems, including Active Driving Assistance, Lane Departure Warning, Active Blind Spot Detection, Side and Top View Cameras and Speed Limit Info.
Outside, M Sport Edition models receive adaptive LED headlights and an available Sakhir Orange metallic paintwork, which was previously available only on hard-core M models like the M6 and M5.
All 6-Series convertible models are fitted with dual front and front side airbags in addition to traction and stability control systems, electronic brakeforce distribution and a tire pressure monitoring system.
Also standard is a roll-over protection system that protects occupants' heads with high-strength aluminum bars that rise up from behind the cabin if a potential roll-over incident is detected.
Further safety equipment comes in the form of Active Protection, which tightens the seatbelts and closes the windows and sunroof if it detects an imminent crash. Afterwards, it automatically applies the brakes to reduce the likelihood of a second collision.
For longer journeys, an Attention Assistant feature evaluates the driver's control inputs and issues an encouragement to rest if it detects signs of fatigue.
As a large premium drop-top with a degree of sporting ambition, the 6-Series Convertible can be cross-shopped against the Mercedes-Benz SL-Class, the Jaguar XK Convertible and the Maserati GranTurismo Convertible.