2017 Mercedes-AMG C63 S Cabriolet

“From the sublime to the ridiculous is only a step” is a well-known idiom that came to mind multiple times during our week with the 2017 Mercedes-AMG C63 S cabriolet. Could that step be the difference between the sublime and equally new C43 AMG cabriolet, with its sweet 362-hp twin-turbocharged V-6, and the ridiculously overpowered C63/C63 S cabriolets, endowed as they are with AMG’s hand-built, twin-turbocharged 4.0-liter V-8 in 469-hp and 503-hp tunes? Or, considering the mass and structural challenges of convertibles, is that step Mercedes-AMG’s decision to risk diluting the street cred of its C63/C63 S coupes, being bad-ass creatures themselves? Regardless of the answer, a C63 S cabriolet is just a step away from two vehicles that could be fairly characterized as sublime, and we couldn’t wait to get our hands on one, drop the top, and determine where it fell.

Other than roof components and some additional structural bracing, there are few differences between the C63 S cabriolet and the C63 S coupe; beyond the M177 V-8, both models share lowered, air-sprung suspensions, beefy brakes, loud exhaust systems, and performance-enhancing wares both hard and soft. Having wheedled some outstanding track numbers in a C63 S coupe instrumented test, we were curious to see how the convertible’s extra 198 pounds would affect performance, so we scheduled a full battery of tests shortly after this droptop arrived at our West Coast bureau.

That’s a C-class?

First, we took a few minutes to just stare—a common reaction among passersby and fellow motorists, whether we were boxed in traffic, loping along Sunset Boulevard, idling at stoplights, or paying parking meters. The C63 casts the largest shadow of any C-class in history: 187.0 inches long and 73.9 inches wide, the latter attributable to beefy, engorged fenders necessitated by the car’s wider front track and 10.5-inch-wide rear wheels. AMG visuals include its signature full-width air intake and matte silver grille splitter up front, as well as side-sill extensions, V8 BITURBO badges behind the front wheels, and a diffuser-style rear bumper with quad parallelogram-shaped exhaust finishers.

This car’s sultry Cardinal Red hue is a $1080 special-order color that conspired with $1000 worth of blackout trim, two carbon-fiber exterior accessory packages totaling $4700, and a $2100 set of forged, staggered-size 19-inch front and 20-inch rear wheels to inflate the C63 cab’s already heady $81,775 base price. But as the sun danced along its shapely red sheetmetal, most graphics rendered dark and all slammed down upon those massive wheels and tires, this C63 S cabrio conveyed more visual gravitas than most models way up the Mercedes-AMG food chain, up to and including the $201K S63 cabriolet we recently tested.

Most of the cabin furnishings come straight from the sedan’s award-winning interior, but even so, this one looked especially rich. Black and gray nappa leather covered the dash, doors, and thin-backed $2000 AMG performance front seats, with matte and brushed aluminum trim, silver switchgear, and bright silver carbon-fiber console trim, the last item a $925 option. A 590-watt, 13-speaker Burmester sound system with perforated speaker grilles is available stand-alone but was included in this car’s $6550 Premium package, which also included the Aircap wind blocker, an upgraded 8.4-inch COMAND infotainment system, radar cruise control with steering assist, an air purifier, power folding mirrors, multicolor ambient lighting, adaptive LED headlamps, and a raft of electronic safety aids. AMG’s color head-up display added another $990 for a rather ridiculous total of $10,515 worth of interior upgrades that, yes, yield sublime results.

Sound: Check. Fury: Double Check.

The M177 barks to life before settling down to a low growl that gets much louder with one button press if, like this one, it’s equipped with the AMG performance exhaust, which at $1250, seems a bargain considering the magnificent sounds it channels. So far, so sublime. But alas, we didn’t even make it out of the lot before encountering a loathsome issue found in other cars with AMG’s seven-speed automatic: a momentary pause when shifting between reverse and drive as the transmission and its multiplate coupler adjusts itself, followed by a lurch when it finally engages. This also happened occasionally when pulling away from a full stop. This is inelegant at best, but infuriating, even dangerous, when pulling onto a busy boulevard from a driveway or when scuttling into a parallel-parking spot with traffic whizzing by, making the use of the optional $1090 self-parking feature (with surround view cameras) impossible.

Most other times, the transmission was terrific, especially with the AMG Dynamic Select system in Sport or Sport+ modes, wherein it cracks off snap-bang upshifts and rev-matched downshifts while the V-8 summons its massive power and torrential torque with shocking immediacy. Three-stage stability control, an electronically controlled limited-slip differential, and brake-based torque vectoring let the driver get deep into the throttle while maintaining grip in corners, even allowing some rear-end slide without deactivating the electronic safety net altogether.

Compromise? What Compromise?

At 4300 pounds, the C63 S cabriolet is the heaviest C-Class we’ve ever weighed, yet our tests revealed that the added weight doesn’t appear to affect its performance attributes except in the most academic of terms. With the M177 boasting enough torque to break those rear 285/30ZR-20 Michelin Pilot Super Sport tires loose even at freeway speeds, the AMG launch control system was invaluable in garnering our quickest acceleration times. And yes, we’re talking quick: at 3.9 seconds from zero to 60 mph before blasting past the quarter-mile mark in 12.2 seconds at 119 mph, the cabrio’s times trailed the C63 S coupe’s times by just 0.2 seconds each. Both cars posted identical 4.3-second 5-to-60-mph rolling starts, and surprisingly, the ragtop beat the coupe in passing tests, with its supercar-like surges from 30 to 50 mph in 1.7 seconds and from 50 to 70 mph in 2.3 seconds, 0.6 and 0.4 second quicker than the coupe.

The cabriolet can also hold on in corners with nearly the same tenacity as the coupe—0.97 g compared to 0.98 g measured at the skidpad. If the cabrio’s added weight made a difference anywhere—and a small difference at that—it was in braking: both cars employed AMG’s optional, $5450 carbon-ceramic front brake rotors, replete with sexy gold calipers, but the ragtop’s 155-foot stopping distance from 70 mph was four feet longer than the coupe’s. That’s still excellent, however, with a firm but natural pedal feel to boot.

The numbers—to say nothing of the actual experience of getting those numbers—are impressive enough, but the minimal degradation in performance on account of it being a convertible impressed us even more. Credit the rock-solid structure of the base C-class cabriolet for much of that, rigidity we could perceive in the absence of body flex or mirror shake. Along with its multilayer, insulated top, the solid foundation affords the cabin nearly the same acoustic properties as the hardtop—at least when the exhaust isn’t in full song.

Easy Being Breezy

The top stayed down most of the time, however, if only to fill our ears with that inebriating exhaust note ricocheting off buildings, overpasses, and other reflective surfaces. Raising or lowering the roof is a silent, one-finger affair that exacts less than 20 seconds of one’s life, and can be performed at up 31 mph should the stoplight turn green while the top is mid-pike. Front-seat wind buffeting is almost nonexistent with the windows raised, but should you want maximum wind-in-your-hair experience, a single button on the console raises or lowers all windows simultaneously.

Like most convertibles, practicality is not this cabrio’s forte. Its short decklid provides access to a trunk that starts out small and becomes, yes, ridiculously small with the top stowed, though the space expands either through the 50/50 split rear seats (complete with elegant, silver remote seatback releases) or the armrest pass-through for skinny items such as skis, or more likely, beach umbrellas.

Far more egregious—indeed, nearly ridiculous—is the C63’s thirst for fuel; during our time, we measured 11 mpg. Sure, our drivers live and work in highly congested areas of Los Angeles and frankly, it’s just plain fun to drive this car hard. It was windy and we had the top down a lot, too. But still . . . eleven mpg? We got 14 mpg in the GLE63 S, the AMG version of the SUV with this engine.

And then there’s the price. If you’ve been keeping tabs on the option prices as we listed them, your sums should add up to $108,960. That’s the most expensive C-class we’ve ever driven, well beyond the nutty $100,595 C63 S coupe we tested. $109K for a C-class. Ridiculous.

Or is it? For a droptop, bona fide Mercedes-AMG model with an outsize personality and road manners more akin to an AMG GT roadster than a C250 sedan, it seems almost justifiable. Consider, too, that AMG isn’t planning cabriolet versions of its next-size-up E63, and that the competitive set is virtually nonexistent—Audi discontinued the RS5 cabriolet in 2015, and BMW will have to give its M4 convertible another 100 horsepower before it’s in the same league. The price may seem ridiculous, but insofar as it will ensure its rarity and exclusivity, it could contribute to its appeal. That, combined with the rest of the C63 cabriolet’s many seemingly ridiculous qualities combine in a way we can only describe as sublime.

Specifications >

VEHICLE TYPE: front-engine, rear-wheel-drive, 4-passenger, 2-door convertible

PRICE AS TESTED: $109,960 (base price: $81,775)

ENGINE: twin-turbocharged and intercooled DOHC 32-valve V-8, aluminum block and heads, direct fuel injection

Displacement: 243 cu in, 3982 cc
Power: 503 hp @ 6250 rpm
Torque: 516 lb-ft @ 1750 rpm

TRANSMISSION: 7-speed automatic with manual shifting mode

DIMENSIONS:
Wheelbase: 111.8 in
Length: 187.0 in
Width: 73.9 in Height: 55.3 in
Passenger volume: 86 cu ft
Cargo volume: 9 cu ft
Curb weight: 4300 lb

C/D TEST RESULTS:
Zero to 60 mph: 3.9 sec
Zero to 100 mph: 10.3 sec
Zero to 130 mph: 14.8 sec
Rolling start, 5–60 mph: 4.3 sec
Top gear, 30–50 mph: 1.7 sec
Top gear, 50–70 mph: 2.3 sec
Standing ¼-mile: 12.2 sec @ 119 mph
Top speed (governor limited, mfr's claim): 174 mph
Braking, 70–0 mph: 155 ft
Roadholding, 300-ft-dia skidpad: 0.97 g

FUEL ECONOMY:
EPA combined/city/highway driving: 19/17/22 mpg
C/D observed: 11 mpg