According to reviewers, the Mercedes-Benz SLK line, launched in 1996, has sold more than a half-million luxury coupe-roadsters. For 2009, rather than messing with a good thing, Mercedes has only slightly refreshed its SLK class.

Externally, the biggest changes are to the nose, which now takes on a slightly more aggressive look, with a split lower front air dam/bumper for more Formula 1 racecar sportiness and a larger Mercedes star on the grille. In addition, larger side mirrors that incorporate arrow-like directional signals help with the lack of rear-view vision when the power hardtop deploys. In the rear, larger tail pipes are divided by a faux diffuser box.

Inside, changes are even subtler, with the most obvious being the three-spoke steering wheel brought over from the C-class sedan. The steering wheel is connected to Mercedes' new "direct steer" variable-ratio steering rack, which produces a 25% quicker steering ratio to provide a more direct, sports car-like feel. Reviewers found the steering feel close to, but still not the equal of, a Porsche Boxster, a direct competitor to the SLK class.

The 2009 lineup features the same three trims as last year with few changes.

SLK300

The entry-level SLK300 was previously badged as the SLK280. It keeps the same 3.0-liter V6, which produces 228 hp and 221 lb-ft of torque. Either a six-speed manual or seven-speed automatic with manual shift control is available at this base level. Standard equipment includes 17-inch alloy wheels, a tilt/telescoping steering wheel, leather upholstery, a premium audio system with an in-dash six-CD changer, and dual-zone climate control.

SLK350

The big news in the SLK lineup is at this trim level, with significant engine modifications to the 3.5-liter V6, which now produces 300 hp (32 more than last year) and 265 lb-ft of torque (a 7 lb-ft gain). The V6's extra punch was the result of lighter pistons, stronger valves, a redesigned intake, higher compression, and a bit of cam tuning. Available only with the seven-speed automatic, the SLK350 makes the 0-60 jump in a very respectable 5.4 seconds. Larger, upgraded brakes are standard. One reviewer was impressed with the SLK350's gas mileage when he recorded an average 29 mpg on a 150-mile highway trip. The EPA estimates 18/26 mpg city/highway.

SLK55 AMG

With the AMG logo, we reach the pinnacle of SLK performance. A 5.4-liter V8 producing 355 hp and 376 lb-ft of torque rockets this roadster across the 0-60 gap in 4.9 seconds. Additional equipment in the AMG includes further upgraded brakes, 18-inch wheels clad with high-performance tires, a sport-tuned suspension, upgraded leather, power heated sports seats with driver-side memory, unique interior and exterior AMG trim, and a power tilt/telescoping steering wheel.

Across the line various options are available, including bi-xenon headlamps, satellite radio, a navigation system, an iPod integration kit, an upgraded surround-sound audio system, and Mercedes' Airscarf system, which directs heated air onto passengers’ necks to extend the top-down driving season. (This is, after all, a luxury sports car.)

For tuner fans, non-AMG models can opt for a "Sport Package" consisting of 18-inch AMG wheels, steering-wheel-mounted shift paddles, a sport-tuned suspension, and some exterior styling additions.

The usual Mercedes care for safety is evident in the SLK line, with ABS disc brakes with brake assist, traction control, stability control, a driver's knee airbag, side and front airbags, and the TeleAid emergency call system all included as standard equipment.

With a metal, foldable hardtop that takes only 22 seconds to drop and let the wind tussle your hair, the SLK line is an all-weather, luxury sports car that has proven extremely successful for Mercedes-Benz.