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The Mercedes-AMG GLA 45 S redefines small SUV performance

By Andy Enright, 28 Jan 2021 Reviews

Mercedes-AMG GLA 45 S Review

Meet Merc's furious 310kW baby crossover you never knew you wanted

Key the ignition off, let your heart return to something that doesn’t feel like a jackhammer in your chest and try to order your thoughts.

The Mercedes-AMG GLA 45 S doesn’t always make that easy. Driven as intended, it’s shockingly fierce and searingly rapid.

Try to prod at its limits on a challenging road and the experience is staggeringly intense. Perhaps it’s the combination of height, compactness and sheer punch that is so mind-scrambling.

Mentally piece together the road that it’s just demolished and it’s clear that this is a small SUV that rewrites what we thought were the extremes of the genre.

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In order to make sense of the violence of what has just happened, perhaps we need to furnish you with some backstory.

Mercedes-Benz has certainly squeezed the A-Class formula until the pips are squeaking. The baby in the Mercedes firmament, the A-Class’ MFA2 platform not only underpins the ever-popular A-Class hatch, but has also been spun into the A-Class sedan, the CLA four-door coupe, a long wheelbase sedan for China and now the GLA baby SUV.

Given that there’s a certain metronomic predictability about some of Mercedes’ product launches that is reassuringly Germanic, having already driven the ballistic Mercedes-AMG A45 S, it was only a matter of time before the folks at AMG got their hands on the GLA.

The results are suitably breathtaking. There has never been a baby SUV with the sort of power and performance that the brains trust from Affalterbach have presented here.

As impressive as the bald facts are – and 310kW/500Nm in a car that weighs less than 1700kg is certainly impressive – we feel it’s incumbent upon us to address the elephant in the room.

The Mercedes-AMG GLA 45 S is, in all practical considerations, a hot hatch on stilts. Most of us are used to paying around $50,000 for some of the very best hot hatches, but this GLA will set you back $107,035.

Despite the fact that this chubby AMG crossover will utterly destroy the very best of that crop in terms of power and capability, it’s an obstacle many buyers will struggle to overcome.

And that’s notwithstanding the fact that, to all intents and purposes, the AMG GLA 45 S is a $93K AMG A45 S with a bit more ride height and a little more space inside.

That price tag also shunts the AMG into the realm of some ultra-talented sports SUVs. A Volvo XC60 T8 Polestar Engineered is around $8K cheaper, a Porsche Macan GTS about five grand more.

Both are slower.

Sit behind the wheel of the GLA 45 S and the genetic link to a $44,000 A-Class is explicit. In other words, there are some compelling reasons why you should shop elsewhere that all seem perfectly valid right up until the moment you prod the silver starter button.

Underneath the stubby bonnet of the GLA is one of the world’s great engines. A 1991cc four-cylinder petrol engine with a single turbo that makes 310kW sound like the very definition of peaky lag and lunge tedium.

It just shouldn’t work. Yet it does. Plug the GLA 45 S into third gear at little more than jogging pace and mash the throttle and it really starts gathering pace from 2500rpm.

By 3000rpm, it has cleared its throat and is really motoring, and the excitement keeps building. At 5000rpm, the exhaust note mutates into a frenzied rush, overlaid by the distant siren-like keening of the twin-scroll turbocharger. By most accepted measures, the acceleration ought to tail off thereafter, but it just intensifies, right through to the soft 7000rpm rev limiter where you snick up another gear and repeat.

For what is ostensibly an SUV, it’s bonkers.

With both port and direct injection, the M139 engine is a fiendishly clever piece of tech.

Needle bearings for the turbo allow it to spin cleanly, propelled by up to 2.1 bar of boost to 169,000rpm, delivering that surreally lag-free feel.

AMG also torque-shaped the engine’s response to make the most of the turbo’s response, lifting the peak torque to 5000-5250rpm, and thus giving the engine a more naturally aspirated feel.

Affalterbach also worked on a smart dual-cooling system, which allows for the head to be kept comparatively cooler for maximum output via a mechanical water pump, while the crankcase is kept a little warmer for lower friction, utilising a second, electrically driven water pump.

Some context? AMG quotes a 4.3-second 0-100km/h time. We achieved 4.4 seconds, which is quicker than a BMW M2 Competition, the difference being the M2 was figured on a hot and sticky dragstrip and the AMG was splashing through standing water in the rain on a private road.

Extracting that performance really couldn’t be easier. Switch the mode dial to Race, ensure the transmission is set to ‘D’, foot on the brake, jab the throttle pedal to the floor, check that the Race Start dash legend has engaged and then sidestep the brake.

The eight-speed dual-clutch transmission blats through the gears crisply. So quick are the ’box’s reactions in Race mode that it has the ability to kick down two gears upon sharp throttle demand before the pedal reaches the end of its travel.

Power is shuffled between the rear wheels via a pair of electronically controlled clutch packs which, when set into the requisite configuration, will even allow an element of power oversteer. It’s a riot.

On road, the AMG GLA 45 S corners with little roll, the microfibre-trimmed wheel tipping the car into corners cleanly. On occasion, the transmission can knock the car down a couple of gears as you pick up the throttle on corner exit, but this rarely shocks either transmission or body, but it can sound a little clumsy.

Keep the car in manual mode instead and you can pluck gears perfectly at will. One caveat is that the space between the right-hand gearchange tab and the column-mounted shifter is pretty tight.

If, like me, you have large hands, it’s entirely possible to turn left with your mitts curled onto the shifter and knock the gear selector up into neutral with a knuckle, depriving you of drive.

For a company as safety-obsessed as Mercedes-Benz, this remains a curious blindspot.

The cabin is otherwise much as you’d expect from an A-class-derived vehicle: that is glitzy but deeply engaging. The MBUX infotainment system is fiendishly complex, but extremely clever.

There’s an excellent head-up display, a fiddly wireless phone charger, decent but fairly firm seats, and multiple drive modes to play with, cycling through Slippery, Individual, Comfort, Sport, Sport+ and Race. Key the car off and it’ll always restart in Comfort, but a press of the manettino-style mode dial pings it straight into your custom-set Individual mode.

Keying off also defaults the grabby lane-keep assist system back to the engaged setting, which requires a tedious sift through the touch-screen menu system to disengage. It also switches the air conditioning off the recirculation mode. If you’re a hay fever sufferer, you’d rather the GLA retained the setting it was left in.

Testing revealed a couple of quirks. One was a seatbelt warning that needed to be cleared down every time the car was started and the other was the vehicle’s habit of activating the pre-crash process (grabbing seatbelts, snatching at the steering, activating the hazards and sounding chimes) whenever the GLA was braked into a particular guardrail-lined right-hand hairpin.

Like all of the A-Class-derived interiors, the brightwork can reflect crazily in midday sunlight with the illuminated air vents positioned in a way to perfectly reflect in the nearside door mirror at night.

For all of its undoubted attributes, it’s something of a struggle to picture the buyer of a GLA 45 S. For it to make sense, you’ve really got to drive it, otherwise, the $25K cheaper GLA 35 AMG would seem to deliver a more compelling value proposition.

And if you are a really keen driver, you’ll rapidly come to the conclusion that the AMG A45 S hatch delivers a higher-fidelity driving experience. What’s more, I’m not sure that the GLA possesses the requisite bandwidth to be that refined small family SUV which then turns into a backroads brawler when you have a bit of time to yourself.

It’s sprung so firmly that your toddlers would grow necks like Dan Ricciardo. Not that there’s anything wrong with that, but it’s not what I’d choose if I was looking for something that could soothe them into the warm embrace of slumber on a journey.

So the GLA 45 S emerges as something of an oddity, albeit a very fierce and crushingly rapid one. It teases at the edge of AMG’s product proliferation plans, but given the demand for Affalterbach’s wares here in Australia, it’ll likely find takers for its particular blend of qualities.

There’s a quirky character ready to reveal itself but it does come at a cost. In delivering the astonishing capability of this powertrain, AMG has saddled this GLA with a distinctly self-conscious price tag.

Or, as Jeff Goldblum once mused, “Your scientists were so preoccupied with whether or not they could that they didn’t stop to think if they should.”

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Rating 4/5

Likes Crushing all-weather capability; amazing engine; interesting tech
Dislikes Road noise; price; niche appeal; some klutzy ergonomics 

Engine  1991cc inline-4, DOHC, 16v, turbo
Power 310kW @ 6750rpm
Torque 500Nm @ 5000-5250rpm
0-100km/h 4.3s (claimed)
Weight 1765kg 
Price $107,035