For the 2006 model year, Mercedes-Benz set the world of automotive styling afire with the introduction of its highly sensuous CLS-Class "four-door coupe." In 2009, this modern classic receives a freshening. Outside, a new two-bar grille with a wire mesh background replaces the four-bar grille and its traditional black backing. The 2009 taillights are LED, and the side mirrors have 32% more glass and incorporate arrow-shaped turn signals. The new rear bumper now boasts trapezoidal dual exhausts that replace oval ones. Of the two CLS models, the base CLS550, which accounts for 90% of sales, receives new 18-inch wheels that sport five twin spokes. Climbing inside, you'll find yards of leather and a dashboard of hand-polished wood, but less interior space than its sibling E-Class offers - the four-seat CLS is all about style. An elegant three-spoke steering wheel gives an unobstructed view of the chronometer-style gauges - speedometer in the center flanked by a tachometer and clock - finished for 2009 in white on a silver background. Fuel level and coolant temperature are displayed via bar graphs. The latest version of the COMAND infotainment system incorporates Bluetooth technology for hands-free cell phone and audio operation. Reviewers report that the system's menus and controls are improved. The CLS63 AMG features a flat-bottom steering wheel, reflecting its performance heritage. A 5.5-liter V8 develops 382 hp and 391 lb-ft of torque that flow through the smooth-as-glass seven-speed automatic transmission to power the CLS550 across the 0-60 jump in 5.4 seconds. The high-performance CLS63 AMG receives its motivation from a hand-built 6.2-liter V8 that shares no parts with its CLS550 sibling's engine. The AMG V8 sends 507 hp and 465 lb-ft of torque spinning through the same seven-speed automatic, but the CLS63 is equipped with the paddle-shifted AMG Speedshift, which is calibrated for 35% faster shifts and perfectly rev-matches downshifts. The 0-60 blast happens in 4.3 seconds according to Mercedes, though one reviewer claims 4.1 seconds. And it stops - it's equipped with six-piston calipers and massive 14-inch rotors in front, and four-piston calipers with 13-inch rotors in the rear. Both cars are equipped with Mercedes' Airmatic suspension, which combines its air springs with electronically adjusted gas-filled dampers to provide a driver-controlled ride experience that ranges from highway luxury-car comfort to exhilaration in the twisties. Reviewers report that the CLS63 AMG, with its tighter suspension, "felt much smaller than its dimensions suggest" when pushed hard on European curving country roads. Safety, as befits a Mercedes, is taken seriously, as the CLS-Class comes equipped with the full complement of airbags, including a driver's knee bag. In addition, the Mercedes' Pre-Safe system is standard - if its forward-looking radar senses an impending collision, the system pre-tensions seat belts, moves seats into safer positions, and closes the sunroof if it senses a possible rollover. Brake control, traction control, and an electronic stability program are also included.