Modern cars, especially modern sports cars, are simply too fast. As market forces compel manufacturers to participate in an unending game of one-upmanship performance leap frog, vehicles have become ever faster over the years in a bid to win headlines and therefore customers.

A fast saloon car today is as swift as a sports car of 20 years ago, or a supercar of 40 years ago. Today’s fastest supercars would embarrass Formula 1 racers of the 1960s, despite carrying far more in the way of air conditioning, stereos and seat belts.

It takes a brave manufacturer to step back from this progression towards mutually assured speed-destruction and replace an outgoing model with one that’s slower. Little surprise, then, that Mercedes-Benz, inventor of the automobile, should be such a pioneer.

The company’s new AMG SLC43 has fewer cylinders, produces less horsepower and accelerates less quickly than the SLK model it replaces. In one respect it does follow a modern trend, replacing a large capacity V8 motor with a smaller capacity V6, its power output propped up through turbocharger trickery, all in the name of reducing emissions and increasing fuel efficiency.

Granted, the SLC43 isn’t much slower than the SKL. The new car will sprint from nought to 62 miles per hour in 4.7 seconds, just 0.1 seconds longer than the outgoing model. It would still win any game of Top Trumps played against a pack of late 1970s supercars.

How to fill all that additional time? With an extra tenth of a second on one’s hands while accelerating to 100 kph, there’s more opportunity to appreciate everything else that the car has to offer. A two-seater convertible is, after all, an exercise in sensory indulgence.

The extra split second could be employed listening to the howling exhaust note produced by the 3.0 litre V6. While not quite as blood and thunder as the previous V8, it’s still a stirring sound, and much more engaging than the tinny racket emitted by the Merc’s arch rival, Porsche Boxster, in its latest four-cylinder guise. Strike one to the Benz.

The Mercedes also does well in the interior design department. The broad sweep of scuttle has a pleasing muscular simplicity to it, accessorised with oversized deco-esque metallic air vents and instrument surrounds.

Slower acceleration will also come in handy by providing more time to find one’s way around the massed ranks of uniform buttons crammed into the central console. While neat and tidy in true German form, they’re hard to navigate in a hurry, making it difficult to pick the right control on the first attempt.

Finding the correct function in the car’s info-tainment interface is also a little tricky. Although the display is larger at seven inches than the SLK’s 5.8 inch screen, it’s not touch-sensitive, so the various menus, sub-menus and sub-sub-menus have to be quested through using the fiddly control wheel. Creating enough time to adequately get to grips with this system would have necessitated a moped engine rather than a V6, but at least the display screen will remain free of unsightly finger prints.

Another problem with the interior is space and lack thereof. The cabin is narrow, even by small roadster standards, so the occupants may experience something of an encased feeling. Leg room and head room are fine, there’s just not much accommodation for the elbows.

Storage for larger items of luggage faces a similar problem. The SLC is a strict two-seater, lacking even the pretend pixie-pew found in the likes of a Porsche 911, so there’s nowhere to casually toss a shoulder bag. The rear storage compartment has a reasonable 335-litre volume – larger than, for example, the 310-litre boot on a BMW Z4 or combined 150-litre and 140-litre front and rear arrangement in the latest Boxster.

Matters take a turn for the worse when the sun comes out and the top comes down. The Merc’s solid folding roof devours a good chunk of stowage when tucked away, cutting one’s baggage allowance to a measly 225 litres.

Mercedes seems to have addressed this problem for those in possession of both luggage and a taste for mid-journey cloud gazing. Ticking the ‘Magic Sky’ box on the SLC’s option sheet enables the driver to use a dimmer switch on the heavens, adjusting the roof from completely clear to completely opaque.

In the event that weather conditions suddenly change, the roof can be raised or lowered at speeds of up to 25 miles per hour – luggage load permitting.

A small car with a small passenger space isn’t all bad. The snugness of fit makes the cockpit feel like a secure and welcoming place to sit. The plump leather seats hold one securely but not harshly, while the chunky steering wheel fills the hand, further underlining the sense of solidity.

Despite the slightly slower acceleration offered by this new model, Mercedes’ marketing folk are clearly indoctrinated into the faster = better orthodoxy. The company is at pains to point out that the SLC is actually faster around a race track than the older, more powerful SLK. Clever suspension has improved grip and handling, returning faster lap times.

Of course, circuit lap times are every bit as relevant to the SLC, even the go-faster AMG edition, as ploughing prowess is to a submarine. This is not a car for high speed cornering; it’s a car for low-speed purring, top down, making sure that everyone can see who’s driving.

Throttle response is crisp, with the turbo chargers spinning up quickly to give little hint of lag. The engine delivers its torque across a wide rev range, pulling strongly from 2,000 to well over 5,000 rpm, reducing the need for frequent gear changes to keep on the boil. Settling down for a long-distance cruise is fairly comfortable. With the top down the cabin is calm enough to hear the stereo at motorway speeds and not worry too much about loose bits of paper making a bid for freedom.

With the roof in place the SLC fares even better, cutting out wind and road noise almost as effectively as a permanent fixed head. The only down side of roof-up travel is that the added hush does allow occasional chassis grumbles to be heard.

On balance, the SLC is a well-judged address to the market niche it’s aimed at. It’s pretty enough to get noticed and equipped with nice, large three-pointed stars to leave observers in no doubt that this is a Merc. It’s enjoyable enough to drive and fast enough to beat anything but the top draw of modern sports cars away from the traffic lights. Customers who want a sports car without wanting to drive it like a sports car should be very satisfied.

Written by James O’Donnell