The 650i is the only 6 Series trim available for 2012; the convertible is hitting the market ahead of the hardtop coupe. The rear wheels are powered by a 400-horsepower, twin-turbo 4.4-liter V-8 engine. It comes with either a six-speed manual or eight-speed automatic transmission at no additional charge … sort of. The manual gets 15/22 mpg, and with that comes a $1,000 gas-guzzler tax.

My test 650i came with the eight-speed automatic, good for 16/24 mpg city/highway. Performance fans won't mind the eight-speed: It shifts quickly and smoothly, and steering-wheel-mounted shift paddles allow for manual shifting.

The 650i also has separate settings that allow you to select a Sport mode that delivers faster accelerator response while maintaining a normal suspension setup. A second sport mode — Sport+ — alters the suspension and stability control system for more serious driving.

For most drivers, the first Sport mode will be all they need. Even in the Normal and Comfort settings — meant for a slightly softer ride — owners get a lot of acceleration on demand, with a healthy exhaust note.

It doesn't have the guttural sound of Jaguar's XKR convertible — a faster, more powerful competitor — but it's just enough to enjoy when the top is down.

For such a large vehicle, the 650i handles exceptionally well. Like the new 5 Series, it doesn't have an overly heavy steering feel, but it still delivers excellent feedback through twisty sections of road. And even with its considerable length, the 650i is relatively easy to navigate through parking lots.

Like the 5 Series, the 650i features a type of regenerative braking to help overall mileage, similar to the technology hybrid and electric cars use to store energy generated from slowing the car down. In our test of the 5 Series, the car's brake feel suffered, but it appears BMW may be working on that issue with successive models; the 650i's regenerative braking system was not as noticeable.

Given its fuel economy ratings, the 650i could use all the mileage help it can get. That said, we doubt most luxury owners look at mileage as a primary factor when buying a V-8-powered convertible.