Perception, positioning – these things count just as much as pampering in a car at this level of the market. Mercedes-AMG have carefully put the new S 63 below its S 65 stablemate, but above the S 500 Cabriolet. This also places it a useful and substantial £50,000 below its perceived rival, the Bentley Continental GT Convertible Speed. So is it positioned as a perceived bargain?

Naturally, the Cabriolet starts off from the basis of the Coupe. It’s the same mechanics, design and extremely pampering four-seater cabin. But above the leather seats is what the factory claims is the largest fabric roof of any current production car. To fit this took more than just chopping off the hard roof.

There’s a bespoke and strengthened windscreen, and at the rear there is extra stiffening and of course storage for the roof. All that helps raise the kerbweight to over 2000kg, so the engine in theory has a bit more work to do.

But it handles the effort effortlessly. The unit in question is the twin-turbo 5.5-litre V8 petrol engine, so you’re looking at a mighty impressive 577bhp and an even mightier 663lb ft of torque. Run that through a seven-speed Speedshift transmission to the 4Matic all-wheel drive system and you have a massive amount of grunt you can lay down, whatever the road conditions.

This is an engine with real muscle, but it’s no sand-kicker, it’s refined, classy, and very fast. That massive torque figure means you can burble around without any effort whatsoever, but put your foot down and you’re catapulted forward with real verve. It’s a bit of a split personality, and one that is hugely attractive and enjoyable, whether you’re rumbling through town or hurtling through a series of sun-drenched S-bends.

The handling is perfectly up to the power, helped by a unique version of the Mercedes-Benz air sprung Airmatic suspension. This comes with adaptive dampers, which allows for two modes, depending on whether you want to be a matinee idol or a hooligan.

Certainly, this sophisticated suspension and chassis arrangement offers a level of control beyond what you’d imagine would be possible for what is quite a hefty car. It’s naturally fairly firm so it can tackle bends with confidence, but that firmness never translates into harshness in the cabin.

In the cabin, with the multi-skinned roof up, you benefit from double-glazed side glass as well as a new sealing technique for the doors, so you’re cossetted and kept away from the ghastly outside world to a degree unusual in a soft-top. Being inside the S 63 Cabriolet is an event, a luxury, and one that is well worth the considerable asking price – especially considering how much less it costs than the equivalent Bentley.

Mercedes-AMG S63 Cabriolet

Location: Nice, France

On sale: Now

Price: £135,675

Engine: V8, 5461cc, twin-turbocharged, petrol

Power: 577bhp at 5500rpm

Torque: 663lb ft at 2250rpm

Gearbox: 7-spd automatic

Kerb weight: 2110kg

0-62mph: 3.9sec

Top speed: 155mph (limited)

Economy: 27.2mpg (combined)

CO2/tax band: 244g/km, 37%