If the AMG GLC 63 S is a car that requires some explanation, then you're not alone. Because, well, we were expecting the non-coupe GLC to arrive, forgetting of course that one mid-size SUV with 500hp couldn't possibly be enough for Mercedes in 2018. As for the naming strategy, it's fairly simple once you know it: 'GL' now prefixes all Merc off-road stuff, 'C' denotes its place in the C-Class family, '63' means it uses the 4.0-litre 'hot-V' V8, 'S' makes it the 510hp version and 'Coupe' is hopefully something that shouldn't take much figuring out, assuming we're all au fait with the current trend for completely ignoring what the word is supposed to mean.
Whatever your thoughts on such cars - we'll assume your tastes are a little more traditional than Sports Activity Coupes - the logic behind a hot-rod GLC is unarguable. BMW has sold 500,000 X6s in a decade, creating a successful niche nobody asked for. Mercedes eventually followed with the GLE Coupe (this car's bigger brother), by which time BMW had already moved on to the smaller X4, the closest rival in ethos to the GLC. Now it's Merc's turn to be avant-garde (old trim level pun definitely intended), by creating a performance version of that model with an X4 M not yet in sight.
Everybody up to speed? Good, so what's it like? Well, even as a pretty staunch opponent of four-wheel drive cars that can't off-road and 'coupes' that aren't very sporty, there are some handsome elements to the GLC. Alright, so they're mostly from the front and in the GT-inspired 'Panamericana' grille, but the overall look probably won't prove as upsetting as, say, a BMW X6. Just don't do what we did and join a convoy of hypercars in the sunshine, because it definitely doesn't look anything but overwrought and chubby then...
Inside it seems like Mercedes is proving to be its own worst enemy, superceding one great cabin with one even more sumptuous seemingly a matter of months later. Such is the case with the GLC. When this style of Merc interior arrived with the C-Class a little while back, it was plush, luxurious and beautifully made. Mostly those traits still apply, though there can be no escaping the fact that an A-Class now has a much more appealing (and advanced) driving environment, with the tacked-on display here especially looking a bit old-hat. That's before you even look at the new Cayenne and its Panamera-inspired layout, or the Audi Q8 for that matter.
Predictably, the twin-turbo V8 does a marvellous job of drowing out any misgivings you might have about the interior by immediately filling it with euphoria. You could be in a Hyundai XG30, and still fall under its charm. While no longer the very newest downsized turbocharged V8 on the block, time has done nothing to dull the impact of the M177. Unlike the cabin, it feels that nothing has come along in the subsequent years, from Mercedes or any other manufacturer, to surpass it. Effortlessly fast, uncannily responsive and wilfully charismatic, the 4.0-litre shines as brightly here as it has does in every other installation since 2014 - perhaps more so.
With the nine-speed auto as found in the E63, Autocar has timed this very GLC from 0-60mph in 3.7 seconds, which feels eminently believable on the road. While it may register more than 2,000kg on the scales, the 63 never feels anything less than alarmingly potent. Not quite as ferocious as the lighter C63, granted, but then even AMG can't defy physics. Yet. The automatic has a few imperfections, and those that there are are probably only highlighted by the flawlessness of that engine: occasional hesitancy at low speed, a delay at redline and a reluctance to change down now and then, though nothing to severely blot its report card.
It's left up to the ride quality to do that. How a car can come from Mercedes, widely known as a paragon for rolling refinement, with this sort of restlessness borders on the unbelievable. Within 100 metres you're scrolling through the AMG Drive Select (and its five settings) for something less punishing, only to find the car is set as cosseting as it can be. While the situation improves with speed, the three-chamber 'Air Body Control' air suspension never loses its fierce sense of tension. You can imagine what Sport and Sport Plus do to it.
Of course the pay off for this is that - should you find a road wide and smooth enough - the GLC is quite incredible to drive quickly. The driver might not be all that comfortable the rest of the time, but they'll be able to marvel at an SUV that flits between direction changes and romps through bends, delivering remarkable composure for something so large. Grip on the road simply isn't a concern, neither is traction, and the optional ceramic brakes feel like they'll last longer even than the current SUV craze. If your idea of driving fun is to point, squirt and devour whatever road runs beneath you, the GLC63 could be the perfect tool.
However, there are naturally limits to the Mercedes' alchemy. Sometimes there'll be the odd traction control intervention, the steering will deliver inconsistent weight and for a moment the GLC seems to be fighting itself - two tonnes trying to make its presence felt on one side; innumerable ECUs on the other. So it can occasionally feel a bit scrappy, then. Although by that point you'll have easily have reached what could be called acceptable on the road anyway.
Which is where the GLC's problems really kind of start, because it does become difficult to see the point. You can have this powertrain in a much more attractive (to these eyes), cheaper, lighter and more athletic coupe with the C63, while the regular GLC offers the same commanding driving position and the practicality of a more traditional SUV. If that's not enough the C63 is offered as an estate. Finally, given the £90k as tested price of this GLC, the 100hp stronger E63 has to be a consideration. All are more likeable cars to our sensibilities than the GLC, largely by sticking to what they know best rather than trying to be five cars in one.
Yet here's the rub. If you want a Sports Activity Coupe - as indeed those half a million X6 customers did - then none of those other 63s are going to cut it. Because they are 'just' saloons, coupes, SUVs and estates - how dreadfully passé. As if to prove the point, the GLC received its fair share of positive attention during its time with us, from those on foot as well as those on two wheels and four. By being a bit different and not quite as imposingly massive as the GLE, it had some passersby intrigued. And that doesn't happen all the time.
Even allowing for a favourable reception, however, and the demand for cars exactly like this, the GLC's shortcomings shouldn't be overlooked. The V8's appeal is indisputable, but with an unsettled ride and slightly fussy interior, the car doesn't feel primed to trouble the fast SUV class leaders.
SPECIFICATION - MERCEDES-AMG GLC 63 S COUPE
Engine: 3,982cc, twin-turbo V8
Transmission: 9-speed automatic, four-wheel drive
Power (hp): 510@5,500rpm
Torque (lb ft): 516@1,750rpm
Top speed: 155mph
Weight: 2,020kg (DIN)
Price: £78,930 (as standard; price as tested £90,925 comprised of ceramic brakes for £4,285, Premium Pack (keyless go, LED intelligent light, sunroof, Burmester surround sound, Artico dashboard and door beltline £2,395, Driving Assistance package (active blind spot and lane keeping assist, cross-traffic assist, Distronic plus with steering assist and Stop&Go Pilot, Pre-Safe Brake) for £1,695, Night Package (AMG sports exhaust with two black chrome plated pipes, AMG bodystyling in black, wheels finished in bicolour), Head-up display for £825, Air Balance package for £350, AMG Performance exhaust for £1,000), Brilliant Blue metallic paint for £685, AMG carbon fibre with aluminium trim for £545)