When BMW brought back the 6-series for the 2004 model year, the big coupe and convertible wore styling penned by the most controversial designer of the decade, Chris Bangle. Now that Bangle's no longer in charge, BMW sheetmetal has retreated to the more conventional place from whence it came, with cars that are handsome and crisp but not shocking. That move suits the redesigned 6-series just fine and the new car is longer, lower and wider than the model it replaces. It's also more muscular, with BMW's twin-turbo 4.4 liter V8 cranking out 400 horsepower and 450 lb-ft of torque. Combine that easy power with active roll control and a hushed cabin, and you've got a big convertible that covers ground deceptively fast. To find out how fast, exactly, we headed to race weekend at the St. Petersberg Grand Prix to get an opinion from someone who knows a thing or two about vehicle dynamics. Warning: the following video features a two-door BMW towing a boat.