The speed-addled gang at AMG wasted little time inturning out a signature version of Mercedes' new CLSslope-bodied four-door "coupe." The CLS55 AMG goesits lesser brethren (which top out at CLS500) at leastone better, with a 5.4-liter V-8 supercharged for 469horsepower and 516 lb-ft of torque. Top speed islimited to 155 mph, otherwise the CLS55 AMG mightsimply blast off into space; it reaches a morereasonable 62 mph in only 4.7 seconds. A five-speedpaddle-shift manu-matic transmission and a speciallytuned version of Mercedes' Airmatic (air-springsuspension) are also part of the program.Eighteen-inch wheels, subtle exterior styling changes,and leather and Alcantara sport seats appeal to theesthete. The AMG version arrives Stateside thisFebruary, about a month after the other CLS models,which it will instantly upstage.