The 2009 model year brings the most significant changes in years to Mercedes-Benz's SL-Class retractable-hardtop roadster, including exterior, interior and drivetrain upgrades. The model competes in the market with the likes of the Cadillac XLR and Jaguar XK convertible.
Three earlier trim levels remain: the V-8-powered SL550, V-12-powered SL600 and ultimate-performance-oriented SL65 AMG, which has a twin-turbocharged V-12. For 2009, the SL63 AMG replaces last year's SL55 AMG. The difference is that its twin-turbocharged V-8 has grown from 5.4 to 6.2 liters. (Mercedes' naming convention, where the engine size dictates the model name, has become unreliable. The SL600 has a 5.5-liter, and the SL65's engine is a 6.0-liter.)
The car's retractable hardtop — one of its signature elements — transforms the car from coupe to roadster in 16 seconds. Changes for 2009 include fundamentally changed headlights that are angular and a bit sinister versus the previous generation's organic forms. They flank a new grille bisected by a single, bold crossmember and bearing an enlarged Mercedes star logo. The hood is domed and creased to carry the line from these new shapes. The lower front bumper flares outward and incorporates a larger grille, giving the car a broader, grounded look. Around back, the tailpipes are now trapezoidal, and the bumper has what Mercedes describes as a diffuser look, suggesting that it serves no real aerodynamic purpose.
The side vents in the front fenders now incorporate broad louvers, which are a welcome distinction when everything from the Ford Focus on up seems to have incorporated the feature. The SL63 AMG version's, however, look more conventional. Eighteen-inch alloy wheels with 10 double spokes are standard on the SL550 and SL600. The AMG models' are 19-inchers.
In addition to the standard bi-xenon headlights, buyers can choose the optional Intelligent Light System, which has five modes for different driving situations. In addition to the more common active (swiveling) and cornering light modes are country mode, motorway mode and enhanced fog lamps.
The 2009 model has a new, more streamlined three-spoke steering wheel and redesigned instruments. One of the most interesting additions is an optional Airscarf, which is two small fans incorporated in each head restraint that blow warm air at the occupant's neck. Mercedes says the objective is to "extend the open-air driving season."
An updated Comand system features improved menus, additional features and the option of a Universal Consumer Interface — a port that accepts portable music players and flash memory and allows them to be controlled through the stereo, complete with onscreen menus. Bluetooth phone functionality and the option of watching DVDs on the screen (when the car is parked) are also added.
The SL550 has a 382-horsepower, 5.5-liter V-8. The SL63 AMG's twin-turbocharged 6.2-liter V-8 makes 518 hp, and the SL600's twin-turbo 5.5-liter V-12 makes 510 hp. The SL65 AMG's twin-turbo 6.0-liter V-12 generates 604 hp. All versions are rear-wheel drive. The V-8 models have a seven-speed automatic transmission, where the V-12s mate to a five-speed automatic. The SL550 can accelerate from zero to 60 mph in a claimed 5.3 seconds. Despite the differences among the other models, Mercedes says they all hit 60 mph in about 4.3 seconds.
An active suspension system, called Active Body Control, is standard. It controls body lean and other unwanted motions and maximizes the ride quality to the road surface. Another active feature, the new optional direct-steer system, adds variable steering ratio to the existing speed-sensitive power assist, which is claimed to further ease low-speed maneuvering without sacrificing higher-speed road feel.
The SL-Class' safety features include standard all-disc antilock brakes, an electronic stability system, side-impact airbags, a driver's side knee airbag, a popup roll bar and active head restraints.