The 6 Series revives a tradition of a big BMW coupe, the last of which ended with the demise of the 8 Series in the mid-1990s. Unlike the original 630csi coupe, which was an independent car, the new 6 Series shares a platform with the recently redesigned midsize 5 Series. The standard engine is the smooth and punchy 4.4-liter V8 that's also found in the 545i and 745i sedans. Thus the designation of 645Ci. A convertible version will follow. The steering system is designed to be quick at low speeds and become linear as speed increases.