These days, the upper echelon of the hot hatch segment is a veritable arms race between just two hi-po superpowers: Mercedes-AMG and Audi Sport. Since Mercedes made its first attempt to muscle in on the Audi RS3’s turf back in 2013 with the first-generation A45 AMG, it’s been a tit-for-tat exchange between the mad scientists in Affalterbach and Neckarsulm as they both compete to make the fastest five-doors on the planet.
This year, the competition gets especially hot. Audi’s box-fresh fourth-generation A3 landed in Australia earlier in 2022 with the flagship RS3 launching just last month, while the second-generation Mercedes-AMG A45 has been patiently waiting for its erstwhile rival to show up since mid-2020.
In Australia, the two hard-hitting hatches come with a very high level of standard specification, with few things on the options list that you, as a driving enthusiast, would actually want or need to add. Besides being German C-segment small cars, the pair also line up very closely on the meat-and-potatoes stuff like power, torque, driveline configuration and drive modes, and their performance metrics are extraordinarily close.
Now let’s say you don’t have a brand allegiance that would sway you one way or another – which one is the most worthy? These cars were never cheap but they’re now more expensive than ever, so if you’re looking for the one that’s going to give you the best bang for your buck, you’ll need to read on.
Price points are an easy place to start, and for the majority of us it’s the size of our budget that’s the greatest limiting factor. Now, given these are the apex predators of their species, neither of these cars are what you’d consider affordable – you’ll need to extract $99,895 before on-road costs from your wallet for the Mercedes-AMG A45 S 4Matic, and $91,391 for the RS3 Sportback.
But even if you add $2500 to get the RS3 in four-door sedan form, the Audi commands a handy lead on the A45 and leaves a bit more change in your pocket for personalisation. Speaking of, the RS design package ($2150) brings contrast stitching and dual-colour upholstery in either green or red, and the Carbon package limited ($6100) adding a carbon-fibre roof spoiler, carbon mirror housings, carbon side skirt accents and gloss-black trimmings for the exterior.
Honestly though… you don’t need them. The RS3 looks aggressive enough without that stuff, which brings us neatly to the next section.
This is perhaps the one area where the RS3 and A45 differ the most. AMG’s hatch looks comparatively sober when lined up against the chiseled edges of the Audi, shrinking into the background thanks to bodywork that, at fifty paces, doesn’t look all THAT different to an A35 thanks to quite subtle flaring of its arches and similar design themes to its bumper plastics. Were it not for the wing atop its liftgate and signature vertically-slatted Panamericana grille, the A45 would blend easily into traffic.
And some may like that, but extroverts will probably gravitate to the wilder persona of the RS3. The RS3 measures 168mm wider than an Audi S3 (the A45 is just 54mm wider than an A35), and there’s greater visual differentiation between the two courtesy of the RS3’s blackout centre grille, chequered-flag DRL pattern, scooped-out rear bumper graphic, shadow-chrome exterior trim, and prominent fender vents aft of the front wheel wells.
The RS3 also has the benefit of a brighter colour palette, with lurid shades of green, blue, yellow and red being available (Kyalami Green and Python Yellow being the most eyeball-searing of the range, and Kyalami Green being exclusive to the RS).
The A45’s colour range is far more muted, with Sun Yellow being the only remotely flamboyant hue available. A dark red and dark blue are also available, but the six other available colours are all monochrome blacks, greys, whites and silvers – the full spectrum of the German rainbow.
Both of these are pushing $100K before on-roads – the A45 certainly breaching it when you factor rego and insurance – so both ship with plenty of equipment for your hard-earned.
Common features are dual-screen cockpits (one in the centre to handle multimedia, the other in front of the driver as an electronic instrument panel), head-up displays, thumping stereos, power-adjustable front seats, leather upholstery, active cruise control, launch control, and heavily-customisable drive modes that allow you to alter suspension, steering, gearbox and powertrain behavior to your tastes.
However there’s one feature that separates the two that’s a lot less sexy, but arguably pretty important from a liveability point of view – boot space. In the A45 you have a segment-average 370 litres of seats-up cubic capacity, but the RS3 Sportback only gives you a measly 282 litres. Even opting for the bigger-booted RS3 Sedan only nets you 315 litres, so those who regularly need to tote some gear may want to bring a measuring tape on their test drive to see if the Audi will be sufficient for their needs.
Okay, this is likely the part the bulk of you will ACTUALLY care about.
Under the bonnet, both the AMG and the RS are engineering marvels. In the Mercedes you’ll find the world’s most powerful production four-cylinder engine, a 2.0-litre inline four that huffs petrol and air that’s pressurized by a fat turbo, blasting out power and torque peaks of 310kW and 500Nm respectively.
In the RS3, there’s one of the world’s most unusual engine configurations – an inline five. Displacing 2.5 litres and featuring an extra piston, you might assume the Audi has a power advantage over the A45. It doesn’t, with its peak power stat ‘only’ hitting 294kW and torque being line-ball with the AMG at 500Nm.
The AMG also has an extra gear to play with in its eight-speed dual-clutch automatic, so one might also assume it will have a gearing advantage over the RS3’s seven-speed, and thus be able to keep its engine within the meatiest bit of its powerband for more of the time. Right? Not quite.
Audi’s factory zero-to-hundred acceleration claim for the RS3 is 3.8 seconds, a tenth faster than what Mercedes quotes for the A45 S. How? The secret may lie in torque – while the A45 and RS3 make the same amount of Newtons, the AMG achieves that number within a narrow rpm window between 5000-5250rpm while the RS3 generates a full 500Nm from 2250rpm all the way to 5600rpm. Given torque is what gets cars off the line, that’s probably the secret sauce here.
But it goes even further than that. Testers in the UK have clocked the RS3 Sportback as being capable of a sub-12-second quarter mile, and multiple outlets across the world have recorded 0-100km/h times that are at least two to three tenths of a second faster than Audi’s 3.8-second claim. Those boffins in Neckarsulm have been sandbagging.
For driveline tech, the two cars take similar paths. The A45 S adopted a clever rear differential back when it transitioned to the current generation two years ago, bringing with it a set of clutch packs for each rear wheel that allow the car to distribute torque from the left wheel to the right wheel depending on conditions and driver demand. With torque vectoring doing its thing, the car can turn in faster and resist understeer by clever power distribution, and it also unlocked something all of you hoons will surely love: a dedicated drift mode.
Cool stuff! Unfortunately for Mercedes, Audi stole the same strategy from their playbook, equipping the RS3 with a rear differential that can do exactly the same tricks – the only difference being Audi is a little shy about the drift thing, instead labelling its rear diff’s slide-enhancing capability “RS Torque Rear” instead of AMG’s far more straightforward “Drift Mode”. Both cars will definitely get sideways in a big way if you have a skidpan or racetrack to play with, and both can be steered on the throttle like a rear-wheel drive car.
Adjustable damper technology is fitted to both vehicles, but Audi does have some extra dynamic sparkle courtesy of a very fast variable-ratio rack with less than two turns lock-to-lock. The Mercedes has a few more degrees of wheel-twirl, which means drivers will be able to whip from left to right faster in the Audi – in theory.
The Audi also comes with the option of carbon-ceramic brakes, which replace the front steel rotors with a pair of carbon items. Does it stop harder than the A45? We haven’t got our measuring tapes out yet, but experience with both the steel and carbon brakes on the RS3 suggests that spending the extra $13K to get them (they’re bundled in with the RS Dynamic Package, which also lifts the speed limiter to 290km/h), is not exactly money well spent. The Audi’s steel stoppers are more than sufficient, and Mercedes has perhaps wisely elected not to offer a similar carbon brake package for its hyper hatch.
One thing the Audi doesn’t have – and perhaps should – is a set of worthy seats. The standard front seats in the RS3 are good enough for the occasional squirt on a public road, but lack upper-body support when heaving into a particularly tight turn. The Mercedes has similar seats as standard, but does at least give you the option of upgrading to genuinely body-hugging Performance Seats as part of the AMG Performance Package, which brings a smattering of extra aero bits, an engine sound enhancer and the aforementioned chairs. For $5790 it’s worth the expense just for the seats alone, and we wish the RS3 had a similar option.
Are you a track day nut? Both cars should delight you on a circuit, and both manufacturers will sell you a set of ultra-grippy Pirelli Trofeo R tyres as a dealer-fit option. With both cars attacking the same circuit on the same tyre compound, the results sure would make for an enlightening and definitive back-to-back test, don’t you think? Now there’s an idea for a comparo…