We like
Sleek style, performance from both the AMG bi-turbo V8 and V6 diesel engines, class-leading fuel-economy, quality cabin, faultless driving dynamics, high levels of safety, cavernous boot, succulent V8 engine note

Room for improvement
Rear accommodation still cramped for tall passengers, bewildering array of controls that might be simplified in the AMG model

IT IS difficult to decide which of the two Mercedes-Benz CLS models available at launch is the most impressive – the bitumen-peeling twin-turbo V8 CLS63 AMG performance flagship or the all-torque V6 diesel-powered CLS350 CDI BlueEfficiency.

Both of these variants of the Stuttgart brand’s new second-generation four-door ‘coupe’ – the one with the distinctive laid-back roofline – are, in their own way, stacked with that rarest of attributes: utter competence.

The big Benz in both guises was completely unflustered during a whirl through central Victoria on sometimes treacherously wet country roads strewn with slippery leaves, tree bark and other debris after a howling overnight storm, leaving this driver with one thought: if the new CLS is not the best car we have had the pleasure of driving, then it is certainly in the same postcode.

Steering weight, grip levels, turn-in feel, ride quality, stopping power – the CLS ticks all the vehicle dynamics boxes and then some.

The fact that the CLS just happens to be one of the most luxurious, self-indulgent and – in AMG-enhanced mode – stirring four-door cars around is just a bonus.

The selling point for the CLS is still, as with the previous generation that along with Maserait's Quattroporte created the four-door ‘coupe’ niche that has emerged as a major battle ground for the European brands, its blend of coupe-like style with four-door, four-seat practicality.

The low roofline does not come without compromise, however, with foreshortened rear legroom and lack of headroom for taller rear-seat passengers compared with, say the E-class or S-class.

Mercedes says the rear seat space – which again offers executive accommodation for only two people – has more room to stretch out and flap the elbows, thanks in part to a bigger footprint from the platform donor car, the new E-class.

While smaller passengers will have no trouble travelling long distances in the individually sculpted, leather-clad rear seats with their own adjustable climate control and built-in central armrest, taller people might feel a little hemmed in.

There is an upside to the rear seats being moved forward to provide adequate headroom for the rear-seat passengers: an absolutely cavernous boot, so deep that one was tempted to shout “hello, is anyone in there”.

In the front seats, it is easy to get comfortable, with lots of whirring electrical adjustment on seats and steering wheel, although the seat adjustment buttons are split into two separate panels, which confuses CLS virgins.

Both models come swathed in leather, including the top surface of the dashboard and, as expected, the AMG model has a more sporting ambience, with piano-black or carbon-fibre trim in place of the polished timber, chunkier suede-grip steering wheel and other touches.

And because the CLS63 AMG is loaded with more bells and whistles – tricky selectable dynamics controls and such – it is quite confronting for the technology challenged. “I wonder what this does” is a frequent refrain for some unfamiliar drivers (guilty).

Over time, most drivers will settle on certain settings and just leave them, for the most part, which is why Benz has accommodated them with a simple ‘AMG’ button on the centre console that locks in the favoured dynamic set-up in case a mate – to whom you lent the car for a run around the block – changes them all.

One of the most joyous moments of the AMG drive is when you poke the start button and revel in the glorious, eager 5.5-litre V8 thunder. That’s 386kW of power and 700Nm of torque talking, unless you have ticked the box for the extra turbo boost from Mr AMG, and then it is 410kW and 800Nm.

Even though the engine has been downsized from the 6.2 litres of the previous model and even with the muffling effect of twin turbochargers, the sound remains one that any red-blooded car nut will love.

It goes without saying that the CLS63 AMG fairly well motors, but we'll say it anyway. With turbos pumping and flappy-paddle gearshifter helping to propel the luxury tourer forward with sledgehammer force, the CLS might well rival Disneyland as the happiest place on earth.

In typical Benz fashion, every step forward in pace is matched by a lift in safety levels. In the case of the CLS, the list is immense, especially on the upscale AMG version.

We particularly liked the CLS63 AMG’s active lane keeping system that nudges the vehicle back on line if it starts to drift across a solid white line.

Frequently, we also felt the vibration through the steering wheel indicating that we were getting a little too close to a broken white line, assuring us that the safety systems were on the job.

The AMG model also features active seat bolsters which inflate when the car corners, bracing the front-seat occupants with what feels like a gentle midriff massage.

Perhaps we would prefer a little more padding in the seat squab, as Benz has not lost its knack for making seats a little flat and hard for our taste.

While we have concentrated on the glamour $263,500 AMG model here – which incidentally is about $18,000 cheaper than the previous equivalent – the V6 diesel CLS350 CDI BlueEfficiency should not be dismissed, especially as it is more than $100,000 cheaper, at $159,200 (plus on-roads).

Packing more than 600Nm of torque, this diesel model – the first in the CLS range – is up for a good time at any time of day or night.

This is underlined by the claimed 0-100km/h acceleration time of 6.2 seconds – impressive for a 3.0-litre diesel in a car that is no featherweight.

At one point on our drive, we came to a full stop at an intersection before accelerating up a steep hill, a task completed so effortlessly that we would have doffed our hats had we been wearing any.

And to return average fuel economy of 6.2 litres per 100km just makes this engine performance all the more meritorious, fully living up to the BlueEfficiency tag that signifies the extra effort applied by Benz to cut fuel consumption.

It has become a cliché that new-generation diesel engines – especially those from the German prestige brands – have become so quiet that they can’t be picked from their petrol counterparts.

In this case, from inside the cabin, this is absolutely true. Only when the door or window is opened can the familiar tak-tak be detected at idle, and even then only at low levels of aural disturbance.

We have yet to drive the V6 petrol equivalent as that model will not arrive until later in the year, but it is going to have a tough job winning us over after tasting the 350 CDI.

For good reason, the phenomenal growth in diesel luxury cars is going to continue, and the new CLS will take up the cause with a vengeance.