Introduction

The Mercedes-Benz SL-Class is not exactly a sports car, or maybe it's more than a sports car. It might be called a high-luxury roadster with a retractable hardtop. 

It's not the world's first, because you could go back to the 1930s, or maybe even the 1920s, and find cars with similar aspirations and accomplishments. The SL-Class delivers elegance to go with its power, and, almost surprisingly, a gentle and nimble driving experience, which is something you definitely can't say about such cars back in the day. 

Today's competitors include such awesome cars as the gorgeous Jaguar F-Type and Aston Martin DB9, the iconic Porsche 911, the brutal Dodge Viper and the thrilling Chevrolet Corvette. 

Now in the sixth year of its generation, the SL-Class is stretching things, so for 2017 it gets freshened to make it more emphatic and expressive, and keep up with those rivals. The body is more svelte (even with the new twin powerdome hood), and the mechanical technology is advanced with a 9-speed transmission in most models. The cabin, however, stays the same, except for the infotainment system that's a bit larger and mounted in the dash rather than freestanding. 

The SL-Class begins with the Mercedes-Benz 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, which we can only scratch our heads about, and wonder what a driver could ever do with it. 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, making us wonder if AMG knows something about those newfangled Mercedes nine-speeds. 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. 

Could be the nine-speeds are all about fuel mileage, chuckle chuckle. As if it mattered. The EPA hasn't tested the 2017 SLs yet, but we're looking at maybe 23 mpg combined for the SL450. And that V12 in the SL65? Maybe 17 combined. But come on, when you've got a V12 under the hood, if you're thinking fuel mileage, you deserved to be slapped upside the head and sent to your local Prius showroom for punishment. 

Safety-wise, the SL-Class is exceptional among performance cars, as it receives so many of the active safety systems in the S-Class flagship sedan. You name the feature, Mercedes-Benz has it. When cars begin totally driving on their own, our money is on Mercedes-Benz to be the first. And we're not saying that's a good thing. 

That goes beyond perceived safety; Mercedes-Benz has a long history of over engineering its cars for safety, and these models have a great real-world record for occupant safety, even if the SL-Class hasn't been crashed by either of the two big national testing agencies, and likely won't be because of how relatively rare it is. 

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. 

Anti-lock brakes, stability and traction control also are standard, as are active headrests, wet-arm wiper blades, active headlamps, 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 caffeine break. 

On the active-safety front, Collision Prevention Assist Plus is now a standard feature, with active brake assist. An available Driver Assistance package heaps on more, including 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. 

Mercedes-Benz bundles a few of the latest safety technologies together in a Driver Assistance Package. Active cruise control integrates with the braking system to detect when a collision is imminent, and to apply brakes to limit damage or to prevent the crash entirely. We have mixed feelings about the utility of this kind of cruise control and the lane-keeping assist that comes with it. However, we feel the blind-spot monitors that complete the trio add a valuable measure of safety, with the ability to help steer the car back into line using directed braking. 

Among the safety options, the rearview camera should be standard at this price. Also on offer are parking sensors and park assist, which uses those sensors and electric power steering to angle the SL into a spot while the driver maintains control over the brake. 

With a new 9-speed automatic, plus a twin-turbo V6 joining the 2017 SL-Class, one that Mercedes-Benz claims as more efficient, we're expecting this hardtop convertible's mileage to improve across the lineup. 

The 2017 SL-Class hasn't yet been rated by the EPA, but last year's SL400 managed an EPA-rated 20/27 mpg City/Highway, 23 Combined. It should be noted that the 2016 model used a 7-speed automatic. The 2017 SL-Class has a 9-speed, so mileage could improve. The SL550 should improve too; the 2016 version was rated at 16/24/19 mpg. 

Step up to the more powerful SL63 AMG model, and it comes as no obvious mileage penalty. Last year's model earned 16/25/19 mpg. If you're looking at the SL 65 AMG, however, you'll only earn 14/21/17 mpg, which is poor, but not terrible considering its immense power. 

Lineup

The SL450 uses a V6, the SL550 a V8, the SL65 a V12, and the AMG SL63 a hotrod V8. 

Walkaround

The 2017 SL-Class front end adds big round LED headlamps with LED running lights, the 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. 

There's an A-wing design in the front that also hints of the old car, leading to a body-colored splitter. The air dams are bigger, and some body panels have been sculpted, making the SL-Class more athletic and chiseled. The effect is 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 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 2017 COMAND 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 eat up much trunk space, 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 quiet as a couple. 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 seems weird, and it's almost difficult, to say that the 362-horsepower twin-turbo 3.0-liter V6 is the slow sister of the SL-Class. What we think we should responsibly say is, for crying out loud, it brings plenty of sweet speed (and 369 pound-foot of torque!), so the other engines are overkill, unnecessary beasts. In fact, if anyone says that, we won't argue one bit. If this twin-turbo V6 isn't enough engine for you in this gentleman's roadster, then you're an unnecessary beast yourself. Or at least a dinosaur. Or maybe someone who simply wants a civilized Viper. Which is where the AMG SL63 with the bigger V8 would come in. 

Fact is, the SL450 feels nearly as quick as the SL550 with its 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. That said, 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 and low speeds and easy throttle, which we blame on the 9-speed transmission, or more precisely, the transmission/engine combination. 

We haven't driven the V12 SL65 yet. Maybe it's a good thing. We might say something bad about overkill. Or we might totally contradict ourselves and say if you're going to have an SL-Class, you only should have the ultimate, a V12. 

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. 

We actually prefer the standard suspension over the sophisticated Active Body Control, or at least we did in the 2016. Mercedes-Benbz has made some meaningful changes to the way the SL-Class rides and handles for 2017. We haven't driven a 2017 SL-Class car yet. 

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. The 2017 version 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.