The new turbo V-8 keeps the "63" name, but delivers its power in even more overwhelming fashion--and numbers: it's a 525-horsepower super sedan in stock form, and 557 horses are available with the appropriate AMG upgrade. It's a big sedan, too, packed to the gills with luxury trimmings and high-tech features, and therefore tips the scales at over 4,200 pounds.
Despite the bulk and power, the 2012 CLS 63 AMG is surprisingly nimble. Part of that comes down to the 255-mm front and 285-mm rear summer performance tires, but mostly it comes down to the suspension and steering. In Sport and Sport+ modes, the car comes alive, firming up suspension settings, quickening throttle and transmission responses, and generally coming into its full AMG-hood. Even the electric-assist power steering (AMG's first) pulls off the difficult balance between proper boost and feedback.
We did have a handful of complaints about the new CLS 63, however, and they mostly stemmed from what makes it such an impressive performance sedan: the overly-stiff suspension. Even in its most relaxed settings, the devilishly-styled four-door coupe is a bit too harsh, jostling passengers and their belongings. It's difficult to really hold too much performance against any performance variant of a standard vehicle, however, and the CLS 63 AMG rises above its shortcomings to be an overall excellent sport sedan.
It's also one of the most luxurious of its segment, with the extra price beyond the likes of the Cadillac CTS-V (last year's Best Car To Buy winner) being immediately evident in the quality, styling, and finish of the cabin. Even compared directly to the entry point of Mercedes' flagship sedan, the S400, the CLS 63 comes out on top.
For all of these reasons, plus the not-really-translatable experience of driving the car itself, the 2012 Mercedes-Benz CLS 63 AMG is a nominee for Motor Authority's 2012 Best Car To Buy.