There’s a point, a little over four seconds after setting off in the 2020 Mercedes-AMG A45 S, that it becomes just a bit silly. You see, even with another empty ribbon of tarmac unwinding in front of me, pretty much anything I do is illegal.
So utterly and useably quick is the little Merc that even with my somewhat relaxed launch, the new forty-five dispatches the posted limit in a shade under the time your food used to be safe on the floor.
Welcome to the world of the hypersonic hatchback. A bright yellow, $93,600 (before options and on-road costs), all-wheel drive, 420hp, four-cylinder, turbocharged mobile explosion. And yes, you read all of that correctly.
The A45 S is the new apex predator in the supermarket carpark. A five-door, five-seat hatch with a sensible 370L boot (expands to 1210L with 40:20:40 seats folded), ISOFIX car seat mounts, and even a five-year warranty.
That near six-figure price tag, on a compact hatch, brings plenty of equipment, including twin 10.25-inch high-resolution displays to adorn the dashboard, Burmester surround-sound system, the full suite of Mercedes driver-assistance technology, multi-beam LED headlamps and even heated seats.
Strangely, though, you score the panoramic sunroof but not the head-up display ($790), and I know which one I’d rather have, especially at less than one per cent of the entry price!
But it’s fair to say you’d expect all that gear on a top-shelf Mercedes. Well, maybe not the yellow paint (which is a no-cost option and one of nine choices), so we’re here to talk about what makes the A45 S special, and as it turns out there’s quite a lot.
While it may look similar to its AMG A35 sibling from afar, from the windscreen forward, the whole front clip including guards, bonnet and front bar is unique to the A45. The toothy ‘Panamericana’ grille and open air dams are functional and hungry, and while cool, our car’s optional aero kit ($2490) adds extra drama and hard-parking cred more than it provides any functional downforce.
Stand behind it, though, and despite the low diffuser and quad pipes, it is clear that this is the hatchback that skipped leg day.
It is impossible to miss the bulging front arches, which don’t even attempt to conceal that the front track is 39mm wider than the rear, and 24mm wider than the A35. There are 245mm-wide Michelin Pilot Sport 4 S tyres all round and standard 19-inch wheels, which are a cool matt-finish aero design as part of our $8090 Edition One package.
Under the blistered bonnet lies the all-new M139 2.0-litre engine, which just pipped La La Land as the winner of the 'most powerful turbocharged four-cylinder engine in series production'. An impressive claim, even without the envelope scandal.
Aligning to the artisan ‘one-man, one-engine’ manufacturing process that AMG holds dear, the M139 is assembled as intended in an all-new facility in Affalterbach. Output is a staggering 310kW (421hp) at 6750rpm and 500Nm at 5000rpm, but even those figures aren’t the most impressive part.
Turbo four-cylinders typically peak early in the rev range, then see torque flatten or even reduce as revs climb. Not so here, the tuning now worked to quickly hit an initial peak (440Nm at approximately 2000rpm), but then continually build torque as the engine spins up, with another rise and final crest late in the rev range.
The engine's bolt-on power-up essentials have been switched 180 degrees so that the turbocharger and exhaust manifold sit behind, next to the firewall. This affords the shortest and most efficient ducting on both sides, improving efficiency and response. The twin-scroll turbo itself is fed by separate channels of exhaust gases from cylinders one and two, then three and four, again for optimal efficiency and response throughout the rev range.
In fact, there has been so much development of this engine that not one component is shared with the old M133. And with the considerable investment made into its manufacturing, we can be sure a compact hot rod isn’t going to be the only recipient of the M139.
It’s not just the engine, though. The whole driveline is unique to the 45-series line-up (A/CLA/GLA), ensuring these tactical road weapons clearly sit above and apart from other models, despite their similar appearance.
No longer simply a ‘tuner’ of existing high-end models, the AMG integration is symbiotic from the get-go, with engineers involved from the initial design stage of the car, and able to plan ahead for the big-power upgrades. In this case, it was known the A45 S would require additional bracing to reduce torsional twisting from the engine, and so a strengthened chassis with a lower ‘shearing plate’ beneath the engine was implemented into the model’s construction to remove any efficiency losses downstream.
A holistic and premeditated assault if ever there were one.
But enough about nano-tolerances and platform architectonics, how does the bright yellow missile deal with the real world?
From door open to ignition start, the A45 S offers that same ‘oooh’ moment that comes with any A-Class experience. The cool turbine vents, cabin lighting and widescreen dashboard are visually impressive, especially at night, but now we’re in and settled you realise that a simple ‘tap and go’ in our world of tap-and-go is not the A45’s game.
Holy cow this thing is complex.
Do you talk to it (hot tip – no), use the console control pad, touch the screen, use the thumb pads on the left, or the right, or maybe just click and twist the pair of sub-action screens on the bottom of the steering wheel?
Even the drive modes – Slippery, Comfort, Sport, Sport Plus, Race, Individual and Doc – would challenge Snow White's memory. What's more, they all offer unique configuration and display options.
There are hours, days, months locked away in the menus and settings of the AMG. So deep is the MBUX interface that it is at times hard to re-find a setting or function you were just using. Rest assured, when they offer a TAFE course to learn Mercedes-101, we’ll see you there.
So, settings ignored, we light the fuse, keep it in Comfort and gingerly pull away.
If you have driven the old A45, especially the pre-update model, your back will remember that the ride was perhaps a smidge firm. Here, the adaptive dampers provide an almost comfortable experience, for a low sporting hatchback that is.
It’s not plush, but it doesn’t crash, meaning a full-day stint in the box seat is very doable. You can even use the ‘energise’ program of the High-Performance Seats (included in the Edition One package, or $3290 alone) to stimulate the lumbar support into a faux massage of sorts. Mind you, for the best part of $100,000, though, it had want to.
Even dialled up to Sport Plus, the ride feels manageable. Tight, sure, but not an assault on your lower molars.
I will say, at regular speeds, the A45 S feels like every other regular bright yellow bewinged hatchback. It’s light, docile, and would easily blend in should you be driving along a road surrounded by daffodils. It will even run single-digit fuel consumption if treated kindly.
Stamp on the throttle, though, and the equivalent energy to a hand grenade exploding every second heads via a new eight-speed ‘Speedshift 8G’ dual-clutch transmission to a fully variable 4Matic+ all-wheel drivetrain.
In its automatic setting, the transmission changes gear quickly but not violently. Your only real advice a new ratio is in play is a tonal shift in the timbre of the exhaust note. Off the gas, a thousand rolls of bubblewrap burst behind you, on it again and the car responds, ready for another round.
Change to the manual mode, and you become a frontline bass player headlining the festival. Pluck or slap a metallic paddle and the AMG dishes up the funk, the exhaust pitch now changing to a howl as you drag every last revolution from each ratio.
Top of third, though, and you’ve surpassed triple digits. Lift off, coast, on again, take fourth and we’re back to backing off. On public roads, the AMG might as well run with three on the tree (it has a column shift after all), as with a 100km/h limit, there are at least four ratios that feel superfluous at this point.
Drive-wise, the car’s standard set-up is a 50/50 torque distribution front to rear, but it is able to adapt to the selected drive mode and performance conditions to send more power where needed, through a snazzy new differential, to individual rear wheels.
Whatever it does, it does it almost too quickly. Boom. Whoosh. Over the speed limit.
Coming into a tighter section of our rural Gippsland tarmac, and the rush returns. Slap it back to second, and blast through the double esses, the road is a little damp but I'm not understeering or oversteering. The under-car trickery is working hard to ascertain the friction of the surface, taking in speed, steering angle, rotation, yaw, and a bunch of other stuff that require long German words to describe, but somehow delivers the car out the other side at a blistering pace.
A torque-vectoring system sees the car continually adjust power delivery through the bends, in both acceleration and braking scenarios, resulting in an otherworldly ability to hold speed at every opportunity.
Tip it in, the car responds. Push harder through the bend, there’s grip for days. Clear the apex with a clear exit and… We’re over the limit again.
There’s even a shenanigans Drift Mode that forces an abundance of drive to the outside rear to help push the A-Class through all manner of sliding showboatery, for… Ah… Expert drivers in controlled situations only.
No such tail-waving hooliganism for me, though, the 45 is a slot car on a winding Scalextric track that seems made from glue. More temp in the tyres, more grip, more movement. Pushing through a light set of left-right-left bends, the advisory sign less than half my entry speed, my only regret that the tasty country pie I’d had for lunch hadn’t been given enough time to fully digest, the bolsters holding me against the lateral g-force… My face greening, the car yellow and cheery as can be. One of us is ready for more.
Had enough? Stomp on the brakes and all this fun stops very quickly, the family-pizza-sized 360mm rotors and six-piston calipers arrest the yellow blur without a hint of protest. We are, after all, keeping to marked limits.
And so here lies the quandary with the 2020 Mercedes-AMG A45 S.
I may have glossed over the fact that our car, as tested, is priced well into six figures on the road. And if you’re cross-shopping a Corolla, then yes, it is expensive for a hatchback. But in reality, the A45 S is a sports car; a genuine racer to revel within the company of grand tourers and coupes… But with five doors and handy boot.
Even if you can come to terms with the shape, can you live with the fact that this car simply cannot be fully explored on a run to the shops, no matter how far away they are? The A45 S is a high-tech race car in disguise, and really must be explored in a performance environment to be fully appreciated.
There are other hatches, there are other AMGs, most of which will suit the majority of your needs better than this one, but if you really must have the hottest of the hot, there is no other option!