Introduction

The Mercedes-Benz SL-Class is not so much sports car as it is small luxury roadster. It's elegant and powerful, while being gentle and nimble. Open-air rivals might be the iconic Porsche 911 Cabriolet and legendary Chevrolet Corvette, while other marketplace competitors would include the gorgeous Jaguar F-Type, and awesome Aston Martin DB9. 

Now in the seventh year of its generation, the SL-Class was freshened and upgraded for 2017 with a more svelte body and new 9-speed transmission. It's unchanged for 2018, except a rearview camera is now standard on the lowest model, the SL450. 

The entry-level model is the SL450 with its twin-turbocharged 3.0-liter V6, making 362 horsepower and 369 pound-feet of torque. 

Next comes the SL550, sporting a twin-turbo 4.7-liter V8 with 449 hp and 516 lb-ft. 

The SL65 flaunts a massive 6.0-liter twin-turbo V12 that delivers a racecar-like 621 hp and unbelievable 738 lb-ft of torque. Finally, there is the Mercedes-AMG SL63, which backs things down a bit, but not much, to a twin-turbo 5.5-liter V8 making 577 hp and 664 lb-ft of torque; it uses a 7-speed automatic. 

The SL-Class hasn't been crash-tested by the government or insurance industry, but it's safe to say that it's exceptional among performance cars, as it receives so many of the active safety systems found in the S-Class flagship sedan. Collision Prevention Assist Plus is standard, with active brake assist. Also active headlamps, LED daytime running lights, and Attention Assist, which monitors the driver for drowsiness and displays a coffee-cup icon on the dash when it's time for a caffeine break. 

The 2018 SL-Class hasn't been rated by the EPA, but the SL450 with the twin-turbo 3.0-liter V6 should get about 23 miles per gallon. Mileage goes down as power goes up in the other models. 

Lineup

The SL450 ($88,200) uses a twin-turbo V6, the SL550 ($112,300) a twin-turbo V8, the SL65 ($222.000) a twin-turbo V12, and the AMG SL63 ($152,800) a hotrod twin-turbo V8. 

The SL-Class comes 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. Options include parking sensors and park assist, which uses sensors and electric power steering to angle the SL into a spot while the driver maintains control over the brake. 

An available Driver Assistance package adds adaptive cruise control with steering assist, an Active Brake Assist system with cross-traffic functionality, blind-spot monitors, active lane control, and Pre-Safe Brake, which will brake at up to 40 percent power, while sounding an alert, if traffic is stopped ahead. With the latter feature, the moment the driver touches the brake pedal 100 percent of braking power is delivered. 

Walkaround

New sheetmetal for 2017 made the SL-Class more emphatic and expressive. The front end features a long hood with twin bulges, and a grille that's more vertical, inspired by the gullwing 300SL W194 that won the 1952 La Carrera Panamericana (after a vulture with a 45-inch wingspan smashed through the windshield and knocked the navigator unconscious). Big round LED headlamps with LED running lights finish off the look. 

There's an A-wing design in the front that also hints of the old car, leading to a body-colored splitter. Big air dams and sculpted body panels make the SL look athletic and chiseled. It's like a brawny sports sedan face on a graceful touring coupe body. From the side it's not the best-looking Mercedes, but from other angles it commands a presence. 

The hardtop roofline and teardrop taillamps seem out of balance with the front end, so as a result it looks best with the top down. 

Interior

The cockpit is precise, like a business jet, with round airplane-like vents and lavish details. The leather is stitched in two rows, and there's enough metallic trim to embarrass an Audi. The steering wheel has a flat bottom, and the shifter is just a tiny knob on the console. What a car this would be with a manual transmission. 

The dash is less flowing and more compartmentalized than the Mercedes C-Class and S-Class sedans. Four chrome-tipped vents anchor the dash that includes a big glowing touchscreen, optional analog clock, and more trim in dark polished wood, aluminum, or carbon fiber. The controls are grouped logically but not all identified with clear icons. The center console is wide, flaring out to hold two big cupholders. 

The COMAND infotainment system has Apple CarPlay smartphone integration. Fancy sound options include a Harman Kardon or Bang & Olufsen sound system. 

The hardtop can go up or down when the car is moving 25 miles an hour or less. The roof panels are automatically stored in a place that doesn't use much trunk space, good thing because it's already pretty small. It only holds a couple of carry-on bags with the top up. 

The seats are wide and deeply scooped, but with 12 adjustments they're supportive for all sizes, including long legs thanks to a bottom cushion extender. They can be heated, cooled or massaged, and warm air can be blown on your neck from the Airscarf. Behind the seats, there's enough room for a briefcase, but behind each seat is a deep bin with a lid. Climbing in and out, with the top up, requires some bending, but not as much as with a sports car. 

Under the hardtop, it's as quiet as a coupe. With the top down and windows up, the effective air deflector makes it possible to have a conversation at 70 mph without shouting. 

Driving Impression

It's a fast lineup. The fact that the 362-horsepower twin-turbo 3.0-liter V6 (with 369 pound-foot of torque) is the slowest engine, mostly indicates the other engines are overkill. The twin-turbo V6 is enough power, period. Actually the SL450 feels nearly as quick as the SL550 with its twin-turbo V8. Not only that, it sounds more strident, if less throaty. 

You have to want the basic nature of a V8 to prefer the SL550. The V8 power characteristic maybe best fits the touring character of the SL. The SL550 lopes along in a refined manner. However we observed some uncouth behavior at low speeds and easy throttle, which we blame on the 9-speed transmission, or more precisely, the transmission/engine combination. 

We think the AMG SL63 hits a sweeter spot of high performance, and it handles the best, although the heavier SL65 is the fastest at 186 miles per hour, and zero to sixty in four seconds flat. Although we haven't driven the V12 SL65 yet. 

As for handling, the SL-Class feels secure as a vault as it rolls down the road. There are five Dynamic Select modes (Eco, Comfort, Sport, Sport Plus, and Individual). Sport mode isn't particularly firm, but it handles sweepers with grace. The electric power steering isn't engaging like a sports car, but it's stable on center and gets quicker off center. 

The standard suspension is excellent. Available Active Body Control moves the suspension into another realm. 

ABC is a full active suspension system, controlled by hydraulics and capable of adjusting its parameters in milliseconds. It helps erase lift during hard acceleration, nosedive during hard braking, and body roll during hard cornering. It includes a Curve Tilting function that helps the car lean into corners up to 2.65 degrees, as a motorcycle rider would, to reduce lateral Gs within the car. 

Summary

The SL-Class offers four distinct models to choose from, built around four engines, bringing four personalities. We think the most modest among them, the SL450 with its twin-turbo V6 making more than enough horsepower, is the most appropriate in keeping with the overall character of the car. Beware the new 9-speed automatic transmission. 

Sam Moses contributed to this report, with driving impressions by The Car Connection. 

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