Mercedes-AMG A 45 S Review 2025: Price, specs & boot space

If you're after a blisteringly fast performance car that's still reasonably practical, the A 45 S is near enough as good as it gets. You just need to be happy with high fuel bills, expensive insurance and a reasonably high cost of entry. 

There's no choice in terms of engine unless you're also mulling over the less powerful and less expensive A 35, although we consider that its own model. Once upon a time, you could buy a standard A 45, but that's long since been dropped from the UK, making the A 45 S your only option if buying new. Although if we were going second-hand, it'd still be the S for us. 

Further simplifying the range, the A 45 S is now only available in 'Plus' form, which includes a lairy body kit and adaptive dampers, among other things. If searching for a used example, we reckon the Plus is the one you want to go for. 

Although it's a very different body style, the coupe-esque saloon CLA 45 S uses much of the same components as the A 45 S, and you can also spec it as a 'Shooting Brake' estate, should you like the idea of an A 45 S but want something more powerful. Sticking with stuff inside the Mercedes-AMG stable, you could consider the A 35, the less powerful, cheaper little brother of the A 45 S. 

Away from Merc, the arch-rival of the A45 S is the Audi RS3. It's also all-wheel drive, and the performance is similar, but it goes one better on the engine front, using a much more exotic-sounding 2.5-litre inline-five. 

Although it's not the same body style, if you're after a compact performance car and have about £70,000 to spend, it's hard to ignore the BMW M2. And for a more leftfield alternative that'd cost you next to nothing to run as a company car, we recommend you take a look at the Hyundai Ioniq 5 N. 

Although the cabin of the A 45 S looks great and uses some plush-feeling materials, there are a few bits that let it down. A lot of the shiny black plastics used are scratch prone, and surprisingly creaky. Then there are elements like the vents, which look brilliant but feel quite cheap and light when you're moving them.

Everything just feels a bit less solid than it does in a BMW or Audi, which is a shame, as the design of the cabin itself is lovely. 

MBUX had a lot of wow-factor when the A-Class was launched in 2018 - it was an impressive setup to see in a relatively small, VW Golf-sized car. Car technology has moved on since then but it remains a good system, especially thanks to recent updates. 

The augmented reality navigation, which overlays turn-by-turn instructions on a feed from a front-mounted camera, is a genuinely useful feature rather than a gimmick, although some cars (including some from Mercedes-Benz) have since gone a step further with an augmented reality head-up display. 

The touchscreen is nicely responsive and relatively easy to navigate, and the 'Hey Mercedes' voice commands functionality works surprisingly well, should you rather not prod the screen. Earlier models also had a laptop-esque touchpad with shortcut buttons between the front seats, which was useful, so it's a pity facelift versions do without. 

Updated models do, however, get AMG Track Pace. For use on track days, it's capable of displaying all sorts of data - known as telemetry - including things like throttle use and braking inputs both on the infotainment screen and on a companion app. So, you can pretend you're George Russel, look through the data and work out how to go quicker around a circuit.

The A 45 S Plus comes with a Burmester sound system, which is excellent. Meanwhile, there are two USB-C ports under the lidded storage compartment between the front seats and a further pair in another cubbyhole for rear-seat passengers. Android Auto and Apple CarPlay connectivity is included as standard.

The A 45 S has 370 litres of boot space, which isn't any less than the regular A-Class. That sounds obvious, but it's not a given. The Volkswagen Golf R for example loses nearly 40 litres of its boot space relative to the regular Golf due to the packaging of its all pushing up the boot floor, but that's not the case with the Mercedes-AMG.

That figure is pretty much par for the course, with the Audi RS3 managing ever-so-slightly more at 370 litres. With the seats folded down (with a useful 40-20-40 split), this grows to 1,210 litres, which, again, is 10 litres shy of the RS3.

You also get a small, lidded compartment under the armrest between the front seats and a small cubby for rear-seat passengers.

It's not cramped inside the A 45 S, but it's not hugely roomy either, much as you'll find with other premium hatchbacks of this size. 

This is easy - there's just the one 2.0-litre inline-four turbo engine with an eight-speed dual-clutch automatic gearbox hooked up for it. It produces 416PS, making 0-62mph possible in just 3.9 seconds. That was supercar territory not so long ago. Meanwhile, find somewhere you can do so safely and legally, and it'll be possible to carry on until the A 45 S hits an electronic limiter at 168mph.

The AMG's wide tyres do result in a bit of tyre road coming into the cabin, but generally, this is a well-insulated car that keeps outside noise levels to a minimum, making long journeys perfectly comfortable. 

The standard Mercedes-Benz A-Class was awarded five-stars by Euro NCAP in 2018 but the test has gotten more stringent since then, and the safety body now considers that rating to be expired. You get plenty of safety equipment as standard, including all of the usual suspects like lane-keeping assistance and autonomous emergency braking. Plus, because the brakes are so good, you probably stand a higher chance of avoiding having an accident in the first place.

The Mercedes-AMG A 45 S is a complex car with a clever all-wheel drive system and a lot of power extracted from a small engine, but so far, so good - we haven't heard of any common issues with these cars as of yet. 

What we do know is the Mercedes-Benz A-Class as a model was ranked a disappointing 69th out of 75 models in terms of reliability in the most recent HonestJohn.co.uk Satisfaction Index, our sister title's ownership survey. Mercedes-Benz as a brand meanwhile sat in 31st for reliability in the manufacturer table, only a few places from the bottom.

The warranty is nothing outstanding, lasting three years or 60,000 miles - whichever comes first. 

The A 45 S sits in a relatively high insurance group 40 out of 50, which is to be expected for a high-performance car. You should always shop around for insurance quotes, but it'll definitely be worth your while here, and it might be worth approaching some specialists. 

Along with the current blanket £195 annual Vehicle Excise Duty (VED), the A 45 is also liable for the government's premium car tax supplement at an annual cost of £425 between years two and five of ownership. Buying used doesn't get you around this.

Currently, the A 45 S is available in Plus trim, and that's your lot. Standard equipment is very healthy, including electrically adjustable front seats, a 10-.25-inch digital instrument cluster with augmented reality navigations, 'Hey Mercedes' voice commands, a head-up display, adaptive suspension, the AMG Track Pace telemetry system, LED headlights, 19-inch forged alloy wheels, a Burmester sound system with Dolby Atmos surround sound, a 360-degree parking camera, and keyless entry.