2010 Mercedes Benz CLS

Five years ago, the term four-door coupe was an oxymoron. But in 2004,

Mercedes-Benz used it to describe the new CLS, and logic was trampled by star-struck customers waving their checkbooks. Rival manufacturers were equally enthralled. Witness the Jaguar XF and the Volkswagen Passat CC. In 2010, BMW will launch a thematically similar four-door, and Audi will chime in with the A7. Mercedes, meanwhile, is readying the second-generation CLS. A careful evolution of the original design, the new low-roof four-seater was masterminded by Gorden Wagener, who was recently appointed head of the design department, replacing Peter Pfeiffer. Sales of the first CLS have run about 40 percent ahead of expectations, and that good news is tempered only slightly by the fact that many of those sales were stolen from the E-class, which looks rather bland in comparison.

Subjectively at least, the second-edition CLS is even prettier than the model it replaces. The banana-like side view is less radical, the curious L-shaped headlamps are gone, and the cluttered front end has given way to a much more elegant appearance. The flanks are more three-dimensional, with rear power bulges, prominent character lines, and flared wheel arches. The A- and C-pillars are better integrated into the arc-shaped roofline. The rear window is bigger, and up front, the grille assumes a more upright position. Like all future Benzes, the next CLS boasts horizontally staggered LED daytime running lights as well as LED brake lights.

Inside, the CLS again gets its own dashboard, seats, and door panels. Like the current car, the new model offers tasteful alternative choices in terms of wood, leather, and color scheme. To further enhance the appeal, Mercedes-Benz plans to introduce new driver-assistance systems, such as automatic lane guidance, a 360-degree-view camera with in-dash monitor, and a second-generation night vision with head-up display.

The engine lineup of the next CLS will see a complete turnover:

• CLS350, 3.5-liter direct-injection V-6, 292 hp; power output increases to 306 hp in 2012
• CLS550, 5.5-liter V-8, 388 hp; superseded by 435-hp direct-injection twin-turbo V-8 in 2012
• CLS55 AMG, 5.5-liter twin-turbo direct-injection V-8, 570 hp; available from mid-2011 onward
• CLS320 CDI, 3.0-liter turbo-diesel V-6, 224 hp; replaced in 2011 by 313-hp CLS350 CDI

The gasoline engines are tipped to incorporate a mild hybrid function in the form of small electric motors integrated in the transmission housing (technology that will debut on the ML and the S-class next year). And all CLS models, with the exception of the AMG version, will be offered with all-wheel drive.

The new mechanicals are all well and good, but, as with the original, the success of the next CLS hinges on its styling. Come late 2010, we'll see whether the new look can fend off the car's rivals.