The CL63 AMG is the driver's car version of Mercedes' grand CL line of premium coupes, which since the current models' introduction in 2007 have staked out a lofty position among premier grand tourers. The 63 gets AMG's renowned 6.2-liter, all-aluminum V8 engine (the 6.3 nomenclature is a homage to the 300SEL of the 1960s). That will bring you 518hp and 465lb ft of torque – enough to make you believe the electronically limited 155mph top speed took some significant potential off the top. More significantly to real-world motoring, it'll do and 60mph from a standstill in 4.6sec, despite displacing 4,600 lbs. And, for the other real world part, it starts at $145,200. Our test car, optioned up with adaptive cruise control, night view assist, parking guidance and blind spot assist, combined with the $2,600 gas guzzler tax to bring the sticker up to $153,685.

In some ways, the 63 is an anomaly within the CL line, which also includes CL500 and 600. While the latter models epitomize the comfortable cruiser, the CL63 recalibrates the grand coupe into a huge bruiser with power to spare. The aggressive air is ably finished off with visual elements including rocker panel extensions, a rear lip spoiler and four oval-shaped exhaust pipes, and a lowered sport suspension with active body control. To my eye it's a great look, purposeful and intimidating without losing the CL's intrinsically elegant lines.

As the numbers noted above reveal, the rocketship appearance is fully backed up when you plant the throttle and unleash all that power. Yet, as you settle back into the gorgeously hand-crafted leather seats, I felt a little out of place – should a luxury coupe feel this stiff, and have this much wind and road noise?

Take a set for a corner and the Drive Dynamic Multicontour seats will do so with you, the side bolstering adapting to the car's movement. It's a little disconcerting at first, but as you get used to it, the seat becomes a friendly participant in your efforts. And, when it becomes overly so, you can reduce its intensity or turn the feature off entirely. There's also a four-level massage function to rejuvenate a tired back on longer trips.

The driver's experience does not include a manual gearbox, naturally, but the paddle shifters on the seven-speed automatic are quick to respond and are augmented by AMG's Speedshift Plus system, which adds double declutching. Switching the autobox to Sport mode causes the transmission to downshift under deceleration, boosting engine braking. Mercedes says the use of double declutching “makes for a more compelling experience and for even greater directional stability when shifting down during cornering,” although some might say that is an ingenious solution to a problem you didn't know you had.

Certainly, the CL63 AMG lacks for nothing in cornering hardware, with massive 18-inch Pirellis that provide tremendous grip and are well matched with the sweetly balanced chassis. Equally impressive are the massive brakes, the 15.4-in drilled-and-vented rotors in the front and 14.4-inchers in the rear provide ample yet smooth stopping power.

Along with all this technology, there's all the copious cosseting you'd expect, the interior's abundance of leather and wood trim offering dignified luxury without any sense of excess. The 14-way adjustable front seats offer an almost endless variety of positions from which to sample the sonic booms on offer from the 11-speaker hardon/kardon sound system, although there seemed a lot of steps to cycle through between the radio and sat/nav. Four-zone climate control regulates temperature separately for each front and rear seat, while rear passengers have their own digital control panel for setting a desired temperature and adjusting airflow.

In short, you'll find everything that such an uncompromising grand tourer should, but with a harsher and louder ride than is typical for cars aspiring to such a niche (although the suspension settings are adjustable). Whether that's an acceptable trade-off or, in fact, a positive is subjective, but if you're looking for a performance match for a Bentley Continental GT – at, by comparison, a relative bargain price – the CL63 AMG could be your ideal.

Andrew Crask

COUNTERPOINT:

First of all let's get one thing clear: this is a car to be cherished, and at $150K, so it should be. It's a major outlay, but after its first year or two, I suspect its value will only ever creep down. It's built to Mercedes-Benz standards, and none of us are going to see the day when 518hp seems inadequate, or a 0-100mph time of less than 11sec seems slow. (It's amazing, therefore, to think that this isn't the quickest model of the range, that there is a 604hp SL65.)

Unlike colleague Crask, I thought the ride was perfect, and that the driver and front-seat passenger are placed perfectly to avoid the worst vertical movement, though road-roar is inevitable with fat tires and chewed up pavement.

Although this is a hefty car, the increase in steering-weight when hustling it conveys to the sensitive driver exactly what is and isn't possible, and there's not even slight play in the wheel: every degree of angle makes a difference, and that, too, is reassuring. Throw in the intuitive gearbox response to your foot on the gas pedal, and you have a car that really will behave like a sports car should you so wish (forget the paddle shifts).

I'm still not convinced it's worth the MSRP, but had I the money, I'd consider a year-old example. And I'd treasure it for a decade.

David Malsher