Recalling the original, 1977-1989 6-series, the exceptionally handsome 2005 BMW 645Ci goes on sale in the United States in the spring of 2004. It features a lightweight aluminum/steel/composite body and an all-aluminum suspension that contribute to its low curb weight of 3528 pounds (European specification). It packs the 4.4-liter V-8 engine from the 7-series, producing 325 horsepower and 330 pound-feet of torque, matching up to one of three six-speed transmissions: a traditional manual, a paddle-operated sequential manual, or a manu-matic. With each successive model, Chris Bangle’s plan for BMW becomes clearer and more agreeable. The 6-series is nothing short of a knockout.