This is the top 'banana' – the Mercedes-Benz CLS63 AMG with 507bhp and 465lb ft of torque. Mildly revised along with the rest of the CLS range, the CLS63 gets a new set of so-called silencers, and the same downshift-blipping auto-box as the AMG C-class. Is this enough to take the four-door uber-coupe from good to truly great?
There’s only one way to find out about this Merc CLS63 AMG: thrash it
You just don’t turn down the key to an AMG Mercedes. I barely bothered to take in the new twin-louvre front grille, LED indicators and taillights, and inch-bigger titanium-finish 19s (actually, to be honest, I did notice those), before ripping the door open and bolting from the car park into the Austrian countryside.
And thank goodness we did. Very quickly we found ourselves heading up a steep, switchbacked hillside, all hairpin bends and loose, greasy surfaces, still damp at midday due to the overhanging trees. Narrow but completely lacking in any obstructive traffic. It was one of those moments when you just put your right foot all the way to the floor.
The CLS looks like a bit of a barge – how on earth did it cope with that?
Despite being nearly 5m long, and weighing frighteningly close to two tonnes, the CLS63 has exceptional high-speed composure. The ride quality on the AMG-tweaked air suspension is far from unbearable, yet the way it controls the big banana’s mass through fast sweepers, tight turns, and rapid direction changes boarders on the unbelievable. Even some fairly nasty surface intrusions completely failed to upset it.
With the chassis so surprisingly good, you might even overlook the engine. Fat chance - the AMG designed and built 6.2-litre V8 is automotive magnificence. Everyone always complains it lacks the low-down shove of the old supercharged 55 engine, but as the new and even more excessively sonorous 'silencers' chuck its glorious big capacity soundtrack at the landscape, you'll find no complaints here about how it handled the hefty local gradients.
It feels and sounds awe-inspiring – accelerative shock swiftly stuns your passengers into total quiet. The 0-62mph sprint takes just 4.5 seconds, matching the fastest time of any 63-engined Merc (only the insanely muscular biturbo V12 65 AMGs go faster), and the 155mph limiter is only a decent straight and short loss of restraint from becoming pertinent.
Oh my. It sounds like you're in love...
Well, you would have thought so. Except that, in common with all AMGs, the whole shebang is let down by the gearbox. As part of this update, the CLS63 gets the same AMG Speedshift Plus 7G-Tronic auto that debuted on the C63. The key word here is Plus – denoting the new double-declutching downshift function, which adds a delicious throttle-blip to your paddleshift downchanges.
But it still isn't good enough – failing to react with suitable speed, and sometimes ignoring downshift requests altogether. Which can be exciting when you're steaming headlong into a corner.
You quickly learn to anticipate its foibles – it's either that or crash. But this weakness causes the CLS63 to come across as slightly disjointed, as the transmission's dyspraxia upsets the rear end – in sharp contrast to the strength of grip and turn-in at the front. Left-foot braking helps ease the transition into challenging corners, but this in turn heats up the stoppers, precipitating fade. And if I'm being picky, the ABS kicks in a touch too early when you're really desperate to shed some velocity.
So is it worth the money?
You're ahead of me here. At £75,050, the CLS63 costs a cool £20,000 more than the next most potent CLS, the 500. But with its four-door coupe design way out at the head of a trend curve, the CLS generally is one of Mercedes' most convincing products. Running costs won't be cheap though – that 19.5mpg combined fuel economy rating is clearly one for the optimistic – but neither this nor its AMG premium stops the CLS63 from feeling worth almost every penny.
And if it's not exclusive or exciting enough out of the box, there's always the Perfomance Package. Available from the AMG Performance Studio, this adds a limited-slip diff, lightweight alloys, more aggressive suspension, and bigger front brakes. If you have to ask how much this costs...
The CLS63 is brilliant but flawed. On the right road at the right time, that engine and chassis coalition is capable of genuinely mind-blowing athleticism. But the gearbox remains – somehow – a disaster.
AMG, please, get hold of a Lexus IS-F and find out how the Japanese get theirs to work.