2018 Mercedes-Benz SL Class

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The Car Connection
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The Car Connection Expert Review

Aaron Cole Aaron Cole Managing Editor
May 7, 2018

Buying tip

We deride the SL450’s V-6 for its unnerving exhaust note, but is the SL550’s V-8 worth $20,000 more? It’s enough to pause for more consideration.

features & specs

AMG SL 63 Roadster
AMG SL 65 Roadster
SL 450 Roadster
16 city / 25 hwy
13 city / 22 hwy
20 city / 28 hwy

The 2018 Mercedes-Benz SL-Class represents the pinnacle of droptop grand touring cruisers. But what does that mean anymore?

That the 2018 Mercedes-Benz SL-Class is a popular pick for mid-lifers pondering their futures may be a small coincidence.

The big, comfortable Benz has a similar predicament in the automaker’s lineup. The newest AMG GT does superlative speed more competently, the new S-Class coupes and convertibles do cruising nearly better than the SL-Class.

For now, the SL-Class is a two-door hardtop convertible with big engines and bigger price tags. Base SL450 models start at nearly $90,000 and can easily reach into six figures with a V-6. Top-of-the-line Mercedes-AMG SL65 models command more than $220,000 for V-12 power and boulevard supremacy. We rate the line at a 7.6 overall. (Read more about how we rate cars.)

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The SL range has largely carried over from last year, aside from a rearview camera made standard on base SL450 models (Eds note: They should have been standard last year, anyway.)

The SL-Class marries a roadster shape to a first-class cabin and brisk powertrains. The base model, which will be the most popular, is a twin-turbo V-6 that makes 362 hp and can sprint up to 60 mph in less than five seconds. A 9-speed automatic tries valiantly to keep it efficient, but motivating two tons of mass that quickly is hardly effortless. It’s more than enough speed for the SL’s primary goal—being a comfortable cruiser—but it’s hardly mellifluous. We also have a philosophical hurdle to clear regarding V-6 engines and six-figure price tags (See: GT-R, Nissan). The SL550 subs in a sonorous 449-hp V-8 for an astounding $20,000 more. From there the performance and prices only get sillier. The Mercedes-AMG SL63 slaps two turbos on a 5.5-liter V-8 for 577 hp and more than $150,000 to start. The SL65 pronounces your success in oil and gas exploration to the world with a twin-turbo V-12, 621 hp, and a $223,000 price tag.

The folding metal hardtop comes down to show the world the smile on your face.


2018 Mercedes-Benz SL Class


All Mercedes-Benz SL models feel special, but they don’t necessarily feel modern anymore.

The Mercedes-Benz SL has evolved over the decades from a rounded shape with gullwing doors, to a me-first 1980s shape, to a period-correct 1990s Miami street machine. They all have a distinct look, but can trace a familial tie.

The 2018 SL is no different, and was slightly updated last year. The current SL tapered its style and its body panels were smoothed for a more athletic look. We call it a 7 out of 10 on looks. (Read more about how we rate cars.)

The SL is uncomfortably wedged between the AMG GT, another two-door coupe with a long nose, and the SLC, which is a two-door roadster that’s similarly long-in-the-tooth.

The tall front end pronounces the SL’s arrival, thanks partly to more-stringent European safety regulations, and its oversize grille and large air dams help mitigate its overall shape. Last year’s tweaks added more aggression to the SL’s face, mimicked throughout the M-B lineup.

In profile, the SL-Class speaks to a grand touring mission, especially in the rear two-thirds.

With the top up, the SL-Class is slightly out of proportion—the roofline is awkward with the teardrop headlights. With the top down, the SL’s styling comes into view.

Inside, the SL marries elegance with more elegance. It’s a business-first approach to interior car design: The layout is more compartmentalized than newer Mercedes coupes, and while it’s certainly stylish, it’s more straightforward than the new S-Class. The button layout, dash, and interior materials speak more to function than form.

There are two rows of stitching through the leather, there's enough metallic trim to embarrass an Audi, the steering wheel's slightly flat at its bottom, and the shifter is just a nubbin on the center console. The small shifter does have the advantage of opening up the cabin and making room for other controls and storage, but we would also like a manual.

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2018 Mercedes-Benz SL Class


The SL-Class has eye-watering numbers, but it’s a better cruiser than anything else. Our inner eardrums can testify to its creamy calm ride.

The Mercedes-Benz SL-Class isn’t about speed as much as it is about carrying speed with comfort. That said, there are impressive powertrains to consider with the SL-Class—even the base V-6 that we’re not hugely fond of.

Starting from a base score of 5, we give points to the SL-Class for its transmissions, range of engines, and its ride for an 8 out of 10. That last point comes with an asterisk, however. (Read more about how we rate cars.)

About the SL-Class’ ride: it’s buttery soft. An optional Active Body Control system with Curve tilting is something Benz bundles into its ultra-luxury cars, but in the SL-Class it nearly works well enough to induce some motion sickness. We’ve found that over a weeklong test, the SL450 quelled motions so well that the difference between what was expected (body lean and movement) and what was received (quelled motion and a whisper quiet cabin) that our inner ears couldn’t reconcile the differences. File under: First world problems.

Under the hoods of most SL-Class convertibles will be a turbocharged V-6 that spins out 362 horsepower and 369 pound-feet of torque. Shuffled through a newly standard 9-speed automatic transmission and rear-wheel drive, the engine is enough to propel the SL450 up to 60 mph in less than five seconds, which is plenty quick for the cruiser. Our only gripe is the noise, which isn’t particularly pleasing. With the top up, the V-6 is quiet enough to run in the background, but with the top down and Sport mode holding gears longer and higher in the rev range, the V-6 trumpets an unnerving noise.

Stepping up to the SL550 brings a traditional V-8 burble and 449 hp (and a better exhaust note). Mated to the same 9-speed automatic, the SL550 hustles up to 60 mph in 4.3 seconds, but shoppers will pay for the privilege: The SL550 starts at more than $20,000 than the base SL450. The 4.7-liter V-8 is satisfying, and almost as fuel efficient, but its cruising speed is nearly the same and the linear power delivery will be nearly negligible for most owners.

From there, better performance requires an AMG badge—and a lot more money.

The SL63 drills a pair of turbochargers into a 5.5-liter V-8 that churns 577 hp and blitzes a 60-mph sprint in 4.0 seconds. Its top speed ends at the limits of your courage, or 186 mph, whichever comes first. The latter AMG model is the no-holds-barred version of Mercedes-AMG’s 6.0-liter V-12, which uses two turbochargers to smother passengers with 621 hp and a sub-four second 0-60 mph run. The speed is prolific and profound, but its $222,000 price tag and two-ton curb weight is in direct contrast to the AMG GT models developed specifically to be quick and nimble.

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2018 Mercedes-Benz SL Class

Comfort & Quality

The 2018 Mercedes-Benz SL-Class prioritizes comfort and class, and is elegant in both respects.

As a rule, two-seaters don’t do well on our comfort system because we prioritize space, hauling capability, and multiple rows of seating—or the exact opposite of the 2018 Mercedes-Benz SL-Class.

Yet, the 2018 SL-Class two-seater notches an impressive 8 out of 10 on our scale for three reasons: It seats two people as advertised, very well, in superlative comfort. (Read more about how we rate cars.)

By the numbers, the SL-Class has 101.7 inches between the wheels, but most of that space is dedicated to the long hood or power-operated convertible top holder (aka trunk). Passengers are jammed between the engine and the rear deck in a manner not unlike a luxury speedboat—and those things are expensive too.

Despite the limited placement, the SL-Class never feels cramped. Soft standard hides swathe the dash and seats, which are power adjustable and boast in-seat massagers. They only get better if your pockets grow deeper or your arms longer.

The seats are deeply scooped with wide buckets for wide American bottoms, but feature adjustable bolsters than can pinch passengers in place with plenty of lumbar adjustability.

There’s little interior storage to be found, but which means you’ll just have to keep a wardrobe in the Aspen home after all. Aside from the usual glove boxes and center console cubby (which boasts two USB connectors), the SL-Class only has a limited amount of storage including a small compartment that features an oversized cupholder. (SL-Class owners apparently are Big Gulp enthusiasts.)

The trunk will hold 13.5 cubic feet of cargo with the top up, or a pair of small soft-sided bags and a smile with the top folded inside (8.5 cubes, to be exact). The top operates at very low speeds or while stopped at a stoplight in less than 30 seconds.

There are more lavish places to sit, but they’re not attached to cars. This one can go 186 mph.

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2018 Mercedes-Benz SL Class


Without official safety data, the SL-Class doesn’t get a score from us. But please don’t ruin that pretty exterior all by yourself.

Federal and independent testers probably won’t ruin a 2018 Mercedes-Benz SL-Class anytime soon and that’s common sense we can get behind. They’re too expensive and sold in small quantities—and too pretty.

We’re withholding our safety score in the hopes that owners don’t test the Merc’s meddle on their own. (Read more about how we rate cars.)

All SL roadsters come standard with front airbags, side airbags that extend to protect the head and thorax, knee airbags, and pop-up roll bars that activate in a rollover accident.

Anti-lock brakes, stability and traction control also are standard, as are active headrests, wet-arm wiper blades, active headlights, LED daytime running lights, and Attention Assist, which monitors the driver for drowsiness and lights up a coffee-cup icon on the dash when it's time for a break.

Advanced safety features including adaptive cruise control, blind-spot monitors, forward collision warning, and active lane control are available, but not standard, on all models. A rearview camera was made standard on SL450 models (ahead of a federal mandate next year) that was previously standard equipment on SL550 and higher models.


2018 Mercedes-Benz SL Class


No SL-Class is lightly equipped, but its infotainment system feels out of touch with a car that can easily crest six figures.

The 2018 Mercedes-Benz SL-Class was the pinnacle of comfort tech and connectivity when it was new. Those days are behind it.

Now, it only takes a short glance over to the other side of the showroom to see where Mercedes has made its bets: the S-Class is better equipped with newer tech.

The SL-Class still ticks all the right boxes for us: It’s outstanding in base models, better with countless options that can be downright decadent, has a good infotainment screen, and “killer” optionals like a whisper of air on the back of your neck or an oragami-folding hardtop that can stow at a stoplight. So why not a perfect score? The SL-Class runs the equivalent of Windows 95 in a MacBook Pro—the infotainment system is outdated. It comes back down to earth with a 9. (Read more about how we rate cars.)

Every SL-Class comes equipped with 19-inch wheels, leather upholstery, premium audio by Harman Kardon, power adjustable seats, a folding hardtop, adaptive dampers, and a 7.0-inch infotainment screen with controller.

That system, which Mercedes calls COMAND, looks similar to the system found in the S-Class but with one important distinction: it lacks a touchscreen. That the SL-Class supports Apple CarPlay is almost irrelevant; running the touch-based system through a clickwheel controller is counterintuitive. To be fair, Mercedes isn’t alone in this respect, but the base setup feels out of step with the rest of the car.

And the rest of the car is downright decadent. An optional Bang & Olufsen audio system is exceptional, custom hides and shades by Mercedes’ in-house Designo can transform the interior to match the exterior, and Mercedes’ Magic Sky Control photochromatic roof that dials in more or less tint on the roof, making it the most expensive set of Transition Lenses on the planet.

AMG models heap on the go fast-looking bits including staggered-width wheels, high performance brakes, a sport exhaust system, and a signed plaque on the engine cover by the engine builder that’s more expensive than most autographs we can think of.

The SL450 starts at just over $89,000 including destination, but can be equipped at nearly $110,000, like our tester. Is that a big ask for a V-6? Maybe.

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2018 Mercedes-Benz SL Class

Fuel Economy

The Mercedes SL-Class isn’t really about fuel-efficiency, and it’s probably better that way.

The 2018 Mercedes-Benz SL-Class trades efficiency for style and comfort—and does it willingly.

Even with a turbocharged V-6 in the SL450, the Mercedes-Benz SL isn’t a fuel sipper. According to the EPA, the SL450 manages 20 mpg city, 28 highway, 23 combined. That’s good enough for a 6 out of 10 on our ratings scale. (Read more about how we rate cars.)

It’s also as good as it gets. The SL-Class also can be equipped with a V-8 and V-12 that predictably craters fuel economy.

The SL550 manages 17/25/20 mpg, according to the EPA’s calculators. The higher powered SL63 returns 16/25/19 mpg—despite having a larger displacement V-8 than the SL550.

If you have to ask, the SL65’s turbocharged V-12 underhood is less restrained than a misbehaved toddler: it’s rated at 13/22/16 mpg.

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February 21, 2018
2018 Mercedes-Benz SL Class AMG SL 63 Roadster

Perfect for big guys

  • Overall Rating
  • Styling
  • Performance
  • Comfort & Quality
  • Safety
  • Features
  • Fuel Economy
  • Reliability
I dont fit in a GT-C and I want a hard top, so this is perfect. S class is a big 4 seater and thats not what I want, I already have a sedan. Im 6'5", and I fit in very few convertibles, but the SL fits me like... + More »
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Styling 7
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