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Mercedes-Benz S-Class Cabriolet 2016 review

It's big, it's heavy and it's an S-Class — but the Cabriolet is also fit, toned and opulent, writes John Carey.

There's a thump and a whirr as the S-Class Cabriolet's automated folding fabric roof completes closure. Only 20 seconds earlier we were basking in the warm sunshine of an early spring noon in the south of France, birds chirping, trees rustling, distant traffic buzzing.

Now the interior is shady … and virtually silent.

The roof-up quietness of this luxurious four-seat convertible is astonishing. Even with its V8 engine revving hard as the car accelerates away from a toll booth and up to the 130km/h autoroute speed limit, the Cabriolet sounds no noisier than its Coupe counterpart.

It's no illusion. Development director Hermann-Joseph Storp says there's no difference in decibels between the hardtop and soft-top at a steady 110km/h. The Cabriolet roof sounds different, with more emphasis on the lower frequencies than the Coupe's stiffer metal structure, he explains, but it's no noisier.

The Cabriolet is the latest addition to the broadest S-Class line-up to date. Mercedes began in 2013 with standard and long-wheelbase limos. Since then it has added even longer and more luxurious Mercedes-Maybach and Mercedes-Maybach Pullman models.

The pretty pillarless Coupe, built on a short version of the S-Class chassis, is its closest relative. The two smallest S-Classes share 60 per cent of their body shells, but the soft-top has different rear-end metal to fit its foldaway roof.

The soft-top is intended as a more laid-back car to drive.

Much of this is aluminium and Benz engineers claim the Cabriolet's bare body weighs no more than that of the Coupe. However, the three-layer roof and its electric actuators add 85kg to the Cabriolet.

"We wanted to give the convertible a different character from the Coupe," says Storp. The soft-top is intended as a more laid-back car to drive.

This was a matter of necessity as much as choice. Benz's Curve Tilting Function (which makes the car's body lean into bends like a motorcycle to enhance cornering power) is standard in the S-Class Coupe but there's simply not room for this technology in the Cabriolet.

When the Cabriolet reaches Australia in September, it will have the same engine options as the Coupe — and a premium of about $30,000.

The $360,000 S500 has a 4.7-litre twin-turbo V8 (335kW) teamed with Mercedes-Benz's latest nine-speed auto. Next in line is the $445,000 S63, with AMG-supplied 5.5-litre twin-turbo V8 (430kW) and seven-speed auto.

Finally, there's the super-exclusive $522,000 S65 with 6.0-litre twin-turbo V12 (463kW) and seven-speed auto, again from AMG.

All models come standard with the maker's latest active and passive safety equipment, including pyrotechnic pop-up rollover protection.

The S-Class Cabriolet is big (more than five metres long) and heavy (over two tonnes) yet it doesn't look flabby. Hefty, yes, but also fit and toned. Roof up or down, this is a very good-looking convertible.

The more relaxed character of the drivetrain feels more in tune with the car's cruisy character.

It's also a fine drive. There's no hint of the body shudders that often afflict open cars and it's also surprisingly agile for its size and weight. The handling isn't sports-car sharp yet the big Benz can be made to flow gracefully on a winding road. Direct steering helps, as do well-chosen settings for the standard air suspension.

The S500 is a little softer and sweeter to drive than the AMG-tuned S63. It rides better and the more relaxed character of the drivetrain feels more in tune with the car's cruisy character.

Still, it's far from slow; Mercedes claims 0-100km/h takes a snappy 4.6 seconds.

The opulent cockpit uses high-quality materials — Nappa leather is the standard upholstery, for example.

The big front seats are supremely comfy and the work of Benz's aerodynamics engineers is obvious in the lack of turbulence while driving roof down (with the optional Aircap system, anyway). The two rear seats are fine for those up to medium height but it can become a little breezy back there at highway speeds.

In the S63, which is noticeably quicker than the S500, the firmer suspension and louder-voiced V8 don't enhance the Cabriolet's naturally relaxed vibe. And the $85,000 saved by choosing the S500 instead is enough to buy, say, a very well equipped C-Class.

Perhaps the S-Class Cabriolet's only shortcoming is the relatively small cargo compartment. It can hold only 250L, on par with a tiny hatch, with the roof down and just 100L more with the roof up.

Other convertibles make a similar compromise — but there are very few so quiet, good-looking and charming as the S-Class Cabriolet.

The V12 rumbles on

The ageing V12 that powers the dearest version of the Cabriolet and other high-end S-Class models will live on in the next generation of Mercedes-Benz luxury cars, says development director Hermann-Joseph Storp.

Mercedes will continue with the V12 as long as there are customers who want it (and can afford it) and has no plans for a new engine to replace the thirsty 6.0-litre monster.

Would you be tempted by a roofless S-Class? Tell us what you think in the comments below.

Click here to see more 2016 Mercedes-Benz S-Class pricing and spec info.

At a glance

Price: $360,000 (est)
Warranty: 3 years/unlimited km
Resale: New model
Safety: Unrated
Engine: 4.7-litre V8 twin turbo, 335kW/700Nm
Transmission: 9-speed auto; RWD
Thirst: 9.1L/100km (est)
Dimensions: 5027mm (L), 1899mm (W), 1417mm (H), 2945mm (WB)
Weight: 2115kg
0-100km/h: 4.6 secs