2008 Mercedes-Benz SLK-Class Performance
This performance review was written when the 2008 Mercedes-Benz SLK-Class was new.
Test drivers find that the SLK's strong handling dynamics provide for a fun sports car experience. Edmunds compliments the SLK's performance, saying there's "no better car currently in M-B's lineup for delivering affordable driving enjoyment." The review also notes that, unlike past Mercedes-Benz endeavors, the newest SLK is a true driver's car: "It admirably delivers solid performance in acceleration, braking and handling." Likewise, the calls the SLK "a marvelous car to drive."
Acceleration and Power
The base SLK280 roadster comes with a 3.0-liter V6 engine that makes 228 horsepower at 6,100 rpm and 221 pound-feet of torque at 2,700 to 5,000 rpm. The SLK350 gets a 3.5-liter V6 that makes 268 hp at 6,000 rpm and 258 pound-feet of torque at 2,400 to 5,000 rpm. According to Mercedes, the SLK350 should reach 0 to 60 mph in 5.5 seconds, while the SLK280 should do it in 6.1 seconds.
Most find the SLK280's 3.0-liter engine adequate, but not mind-blowing. BusinessWeek calls the engine "quite quick," while Kelley Blue Book says it feels "plenty peppy, but not rocket-ship fast." notes that the V6 "isn't the fastest engine you can get for $45,000, but it is tuned to respond instantaneously to demanding drivers, and powers the car from zero to 60 in a flashy 6.1 seconds."
But for more powerful performance, Kelley Blue Book concludes "the SLK350 is the way to go." Consumer Guide says its 3.5-liter V6 "has ample thrust from any speed." Cars.com says acceleration is "energetic and refined with the 3.5-liter engine."
Of course, the SLK350's larger engine means a disadvantage at the pump. According to the Environmental Protection Agency (EPA), the base SLK280 is expected to net 17 miles per gallon (mpg) in the city and 25 mpg on the highway with the manual transmission, and 18/24 mpg city/highway with the automatic. The SLK350, by contrast, should get 17/23 mpg city/highway with the automatic and 16/23 mpg with the manual. Premium fuel is required.
The SLK280 comes standard with a six-speed manual transmission or optional with a seven-speed automatic. The SLK350 comes standard with the automatic, which includes Touch Shift for manual gear changes. Most test drivers are satisfied with the manual gearbox because it makes the SLK "feel more like a sports car," according to Consumer Guide. Motor Trend says the six-speed "has snicky, quick action, making it one of the best gearboxes in the sports-car biz." The finds it "wonderfully responsive to the driver's directions." Finally, The Auto Channel describes the transmission as "a delight to use" and says "downshifting to gain quick acceleration was better than with an automatic."
The seven-speed automatic, which can be manually shifted with buttons on the steering wheel, is also well-liked. Automobile Magazine says it "works extremely well at all speeds, especially around town, exhibiting none of the herky-jerky upshifting that characterized the first-generation SLK230's powertrain." says the transmission is "one of the few automatics I've actually liked. It seemed to know intuitively when I wanted to up- or downshift -- and accomplish the job in a nanosecond."
However, a few test drivers aren't as impressed. "I can't say, though, that I'm a huge fan of the seven-speed automatic transmission," comments BusinessWeek. "It has two more speeds than usual, but it doesn't seem to gain much efficiency from this technological refinement. It seemed a little racy to me at times." In addition, Cars.com finds that the auto's operation "can be rude. It can get jerky at low speeds in lower gears and delivers a sizable jolt if you hit the gas pedal while slowing down."
Handling and Braking
Ride and handling are the SLK's strong points. Motor Trend describes them as "well-refined, without much compromise to either. You feel bumps and expansion strips on the highways, but there's enough compliance to keep them from being uncomfortable." describes handling as "world-class," adding, "Matchbox cars don't turn as tightly." BusinessWeek notes the SLK's handling is "more sedate than in, say, a Porsche Boxster, which is in the same price range," but still says the SLK is "sporty enough for most people."
The rear-wheel drive SLK features an independent three-link front suspension and independent five-arm multilink rear suspension. Motor Trend finds it well-balanced, making the SLK "an ideal sports car for mountain road drives. It's crisper and sharper in every input versus the old SLK320." Cars.com says the SLK's ride is "easily tolerable for a sports car of this caliber. Sure you feel the bumps, but most are dispensed with rather handily." Car and Driver compliments the chassis for being "light on its feet, tight in the structure, and immensely responsive to a driver's whims. Lapping up the open road, the SLK demonstrates resolute body control but no brittleness to the ride as you'll find with the Crossfire."
To aid control, all the SLK comes equipped with an Electronic Stability Program that automatically brakes the car to help correct understeer and oversteer. The Consumer Guide says it "delivers sterling high-speed ride control, but turns choppy on sharp ruts, ridges." The found the special suspension "plenty stiff" and feels it "helped the roadster corner like a race car. Fun. The ride could get rough, but this is a sports car, after all." But Consumer Guide advises that "unless you drive mostly on unblemished surfaces, there's not enough gain to offset choppy ride quality."says the system is "one of the best available -- constantly monitoring steering inputs and quickly acting to correct errors, such as turning too quickly into a curve." For a sportier ride, the optional AMG Sport Package adds high-performance tires and a lowered sport suspension.
The SLK's power-assist rack-and-pinion steering receives good reviews, with AutoWeek saying it "feels perfectly weighted." Car and Driver adds, "The nose cuts its arcs with go-where-she's-aimed steering" and Consumer Guide comments, "Any SLK has precise steering, adroit overall balance, grippy cornering even in bumpy turns." Likewise, says the SLK "turns more tightly than those narrow scooters my kids do stunts on." One of the only criticisms -- and a minor one at that -- comes from Kelley Blue Book, who says, "You'll find that the steering is precise but heavy, requiring authoritative input from the driver."
Helping to stop the SLK are dual-circuit power-assisted four-wheel disc brakes with an Anti-lock Braking System and Brake Assist. AutoWeek calls the brakes "super strong -- they bring the car to a stop so quickly that the only thing you have to ensure is the car behind you has room to stop, too." BusinessWeek describes braking as "more than adequate" and Consumer Guide says its "powerful, undramatic." However, brake pedal feel isn't ideal -- at first, anyway. "The first time I hit the brakes it was like running into a wall of dough. I had to learn how to moderate my brake foot," explains The Auto Channel. Likewise, the says the brake pedal "has a soft feel that takes getting used to."