If imitation is the sincerest form of flattery, there must be some rosy red cheeks at Mercedes-Benz these days.

It’s one thing to inspire the rest of your industry to design cars that follow certain design cues, it’s quite another to invoke an entirely new type of car and have your competitors clamour to match it in the market place.

That’s what Mercedes-Benz did when it introduced the CLS back in 2004.

Based on the medium executive E-Class model, the CLS copied its four-door saloon layout but added a beguiling, swooping coupe exterior.

Then the German manufacturer made life even more difficult for its rivals, by handing the model over to its in-house tuning division, AMG, for a thorough going-over in the performance stakes.

The result was the CLS 55 AMG, later developing into the CLS 63 AMG, the new version of which has broken cover in 2011.

It speaks volumes of the CLS that the competition is only now beginning top catch up with any conviction. Porsche’s Panamera, the BMW 5 Series Gran Turismo and Audi’s A7 offer a similar appeal.

The CLS has even had an effect on traditional saloons where manufacturers haven’t been provoked into producing new models - look at the swooping design direction of the Jaguar XF and XJ.

Not many have managed to match AMG’s take on the CLS in terms of performance, however. The Panamera and Aston Martin Rapide can rightly lay claim to equal prominence but, arguably, neither carries off the high performance, saloon-coupe permutation with the same effortlessness as the Mercedes.

While the AMG division has seen to it that the graceful exterior of the CLS has been suitably refined in keeping with the high performance - 19-inch alloy wheels, dramatic body kits and even carbon fibre lip spoilers where the optional Performance Pack is specified - it’s beneath the skin that the majority of the magic has been worked.

Mercedes’ smooth petrol and diesel units are by no means unattractive options, but the twin-turbocharged 5.5-litre V8 that AMG has been employing since late 2010 is beyond the call of duty.

The weight of the unit has been reduced using a fully aluminium crankcase and lightened exhaust system, while power, courtesy of piezo injectors, camshaft adjustment, air and water intercooling and those two turbos, is up to 525bhp; 557bhp with the Performance Pack specified.

As a result, it will come as no surprise to learn that the CLS 63 AMG is a formidable performer on the road. 62mph is reached in 4.4 seconds in standard form, with top speed limited to 155mph. But the model is not just quick in a straight line.

A redesigned front suspension system allied to rear air suspension and in combination with an advanced electric power steering set-up means the CLS 63 AMG belies its considerable size in terms of handling.

Agile and responsive not just in terms of throttle, but also steering input and braking - particularly with the ceramic disc option - the car feels at home being pushed to the limit.

Adjustable suspension allows the driver to control the firmness and reduce lean in corners while the sports modes for the seven-speed AMG Speedshift MCT-7 transmission are notably impressive; blipping down the gears intuitively under braking to offer a racing approach without having to use the manual paddles located on the steering column.

Yet, almost as impressive as the CLS 63 AMG’s sporting performance is its adjustability. As a boulevard cruiser it’s equally competent. The addition of a stop-start system has helped improve fuel economy by an astonishing 32 per cent, making the model more at home in town than ever, but on a sedate journey the V8 burbles through the four chromed tailpipes with delicious menace.

Thanks to the seven-speed transmission and strong build and refinement, a sedate cruise can mean anything from 17 to 70mph. Built using the E-Class saloon platform the CLS offers a similar amount of space for occupants. A strict four-seater with a laid back approach in the rear, head room and accessibility is a little restricted thanks to the sloping roofline, but that’s really a small price to pay for additional external appeal, as the popularity of the CLS testifies.

As attractive to drive as it is to gaze over, the Mercedes-Benz CLS 63 AMG combines effortless grace, executive appeal and sports performance in a package that will keep its rival on their toes for some time. - Richard M Hammond

Facts at a glance

Model: Mercedes-Benz CLS 63 AMG, �TBC.

Engine: 5.5-litre petrol unit developing 525bhp and 590lb/ft of torque.

Transmission: Seven-speed automatic transmission as standard, driving

the rear wheels.

Performance: Maximum speed 155mph (limited), 0-62mph 4.4 seconds.

Economy: 28.5mpg.CO2 Rating: 231g/km.