The new Mercedes-AMG C 63 S Cabriolet builds on the already excellent C-Class Cabriolet by ramping up the sports car factor – and then some. This confident four-seater melds the best of the C-Class and AMG characters, with an emphasis on sheer driving pleasure rather than comfort. It boasts the sector’s sole twin-turbo V8, too; the BMW M4 Convertible has a twin-turbo straight-six, while the Jaguar F-Type R lacks rear seats and its V8 is supercharged.

The C 63 S Cabriolet boasts all the expected AMG character traits. There’s that 4.0-litre V8, which produces 469bhp in regular form or 503bhp in the S tested here. Our version also features dynamic engine mounts that firm up when you start pushing on.

Mercedes’ multi-clutch transmission (MCT) sends power to the rear wheels, and there’s a host of drive modes for the powertrain and suspension. The latter features standard-fit ‘ride control’ – essentially adaptive adjustable dampers – with Comfort, Sport and Sport Plus modes. Track is widened over that of the regular C-Class, and there’s a limited-slip rear diff. This is electronically controlled on the S, which also gets uprated front brakes.

Entering the cabin via the rather long doors, you’ll find leather and Alcantara trim. The heated, motorised driver’s seat moves forwards and downwards to allow access to the rear, where two passengers will find they have sufficient space to get comfortable only if they’re below average height.

The cabrio shares the C 63 saloon’s well designed dash layout and widely adjustable driving position. The conventional analogue white-on-black instruments hint at enhanced performance, and everything from the suede steering-wheel covering to the knurled metallic climate-control switches feels suitably high quality.

A chrome-finished lever operates the fully automated cloth hood, which takes less than 20 seconds to lower or raise, at up to 31mph. It stows out of sight in a compartment immediately above the car’s boot. The load space is 360 litres with the roof up and 285 litres with it down.

Even on our freezing-cold test day, which meant the electronically governed launch control automatically deactivated, the C 63 S Cabriolet recorded a highly impressive two-way 4.6sec 0-60mph average. Throttle response is near-perfect even through forced induction, and power delivery beautifully balances torquey linearity and a dramatic climax. The car certainly lives up to the AMG hype – and the exhaust sounds every bit as rich, characterful and enticing as you’d hope, without intruding into the cabin. Roof down, front passengers are decently protected from the elements; the rear occupants, less so.

Of course, in keeping with the brand, this AMG machine is so much more than merely a slick soft-top boulevardier. It’s every bit as yobbishly damped and unapologetically well connected to the road surface as the equivalent saloon and coupé. Hardcore enthusiasts, starved of big cabrios done with true sporting commitment, should be celebrating.

The suspension doesn’t preclude comfortable cruising, but its very firmness prove noisy and clunky. It’s worth it, however, for its adjustability and uncorrupted, rear-driven, grunt-over-grip handling. That comes courtesy of taut and progressive body control, keen, compelling yet still intuitive and natural handling, and well judged, feelsome electromechanical steering. The body structure is more than stiff enough to take it.

When it comes to costs, the Mercedes-AMG C 63 Cabriolet looks good. It has predicted strong residuals of almost 40 percent after four years. If it’s driven gently, it should return 27mpg; if it’s not, you’ll revise that to below 10mpg. When it comes to speccing your purchase, remember the C 63 S includes adaptive dampers and active diff as standard. Mercedes’ Premium Pack is a worthwhile £1295, but avoid the larger, ride-corrupting alloys.

The AMG C 63 is not far off proper sports car money, with an equivalent BMW M4 costing £7000 less. The Mercedes-AMG does have a bombastic V8 and outstanding performance and handling, though, combined with a luxurious cabin – and while there’s no quarter given on rolling refinement, when your product is as singular and truly luxurious as this, people will pay. Its all-round usability means the strings to its bow are many, yet it remains dedicated to its sporting purpose in a way that’s almost unprecedented in a car of this ilk.