Mercedes-AMG S63 Cabriolet new car review

It's not every day that you get an orgasmic hot-stone massage and a tan at the same time, all while having your ears enervated by the angry grumbling of a 5.5-litre, twin-turbo, hand-built V8 engine.

Perhaps it is this kind of multi-tasking time-management - I was simultaneously traversing large swathes of America at 120km/h - that makes people willing to spend a whopping $444,715 on Mercedes-Benz's AMG S63 Cabriolet.

Yes, that is a lot of money, almost enough to buy you the super-luxurious Mercedes-Maybach S600 ($448,610), but you can't get a tan in one of those.

In theory, an S-Class Cabriolet is pure bonkers, because it's a bit like chopping the roof off your private jet, yet it only takes one glance at all its hulking glory in the metal for this car to make big, gorgeous sense.

The S63 Cabriolet is almost as vast and heavy as the limo, at more than five metres in length and over two tonnes, and is built on a shortened version of its chassis. But it is a much prettier car, with its pillarless coupe shape, and looks decadently delicious from front on, and quite lovely from most angles (it's a bit hippy from directly behind), particularly with the roof down.

The big change from an S-Class is that you don't want to sit in the back of this car, nor should you, because your knees will hurt, and nor can you choose to throw the bodies of your business rivals in the boot. The Cabrio's load area is just 250 litres, which is considerably less than you get in a Mazda3, but enough for a couple of overnight bags.

Frankly, despite its multitasking genius, practicality is not what anyone buys an S63 Cabriolet for.

What they're after is a combination of luxury and sportiness that is both baffling and deeply amusing.

I understand why someone might want a big, louche car like the S-Class Cabriolet, because it is simply a stunning way to soak up the miles. The seats, even when you haven't selected one of the six massaging options, are supremely comfortable and even on cold-but-sunny days (what I like to call "Canberra days"), you won't mind lowering the roof because you can stay warm enough with your heated seats, steering wheel and armrests, as well as the Airscarf, which blows warm air on your neck and is so effective you start to feel like you've got sunburn after a while.

The ride quality of this car also beggars belief, as it does in all S-Classes, because it seems as if the contact between road and tyres is happening in some far off place that doesn't concern you. Bumps aren't just soaked up, they are told to go away, quietly.

It's also fantastically quiet, with a multi-layered, sonically sealed roof that provides the exact same levels of NVH at 110km/h as the hard-topped coupe version, according to Benz. It's easy to believe.

Roof down, the Cabriolet also offers a new system called Aircap, which raises a tennis-net sized air deflector above the rear seats, and a large flap on top of the windscreen, all with the aim of getting no wind in your hair whatsoever.

It's all remarkably effective, reducing wind buffeting so that you can just enjoy the warmth of the sun on your skin and the weird feeling that a stranger who's just eaten a kilogram of jalape?os is breathing on the back of your neck. It is noisy, however, and sounds like you're actually wearing a cap and have stuck it up in the wind. Fortunately you can easily drown it out with the awesome Burmester 3D sound system.

Just a word of warning about those seat-massage functions, by the way; you really shouldn't use them, particularly the hot-stone ones, while you have passengers in the car, because it is impossible not to make embarrassing groans of pleasure while they're working on you. The Active Massage function, which instructs you to push your muscles back against the pressure points being worked on, seems a bit like hard work, however.

Because I am a dedicated journalist, I tried all six massages, and I must admit I got out of the S63 after five hours of driving feeling like I'd just been to a spa. Never has driving that far through the slightly scary Bible-belt surroundings of the Deep South (I lost count of the Baptist churches at 3000) been so relaxing.

So, the effortless luxury, I get, but why would you step up to the AMG version, with its hugely angry engine making 430kW and 900Nm, and a 0 to 100km/h time of four seconds flat?

Perhaps because you enjoy laughing out loud at the sheer absurdity of things.

Plant your foot in the S63 and you are rewarded with the most pronounced rearing-horsepower effect I have ever experienced. The rear of the car squats as all that power finds the road, and the bonnet, despite its hugely heavy engine, seems to rise up in front of you and you find yourself staring at the sky, and giggling. Moving this much car that quickly surely causes old Isaac Newton to roll in his grave and snap his pencil.

The AMG's acceleration seems to come in two waves, a surge of effortless grunt and then an "oh you want to get serious do you?" thrust, which whips back your neck as you rush forward.

All that torque, nearly a Newton kilometre of it, is enough to flatten mountains, meaning you can climb even the steepest of hills with the laziest of ease. It really is a crushing roar of an engine, and after a few hours, the extra spend on the AMG version starts to make some kind of sense. When the car your buying seems unnecessary anyway, why not go the whole fatted hog?

Compared to an S-Class sedan, the S63 Cabriolet corners like a race car, with none of that floaty-boaty feeling you get in its cruise-ship sister, yet even in the sportier settings, the AMG-fettled convertible still seems to err towards luxury rather than sport.

Make no mistake, you can hustle this big beast along a winding road at pace, and with commendably little body roll, but there's less feedback through the slightly light steering than other cars wearing an AMG badge offer.

The S63's buyer - and Mercedes-Benz Australia has already found a few locally - either cares not for such hard-edged sensations, or has a C63 for that kind of fun anyway.

As a car that provides the very best of both worlds, punishing performance and lazing-in-the-sun luxury, the S63 AMG Cabriolet is a stunning success. 

2017 Mercedes-AMG S63 Cabriolet specifications

Price: $444,715 before on-road costs

Engine: 5.5-litre twin-turbocharged V8 petrol 

Power: 430kW at 5500rpm

Torque: 900Nm at 2250-3750rpm

Transmission: seven-speed automatic, all-wheel drive

Fuel use: 10.2L/100km