Mercedes-AMG A45 S: 2025 Hyperhatch Review And Specs

The Mercedes-AMG A45 S stands as a benchmark in the hot hatch segment, packing the world’s most potent production four-cylinder engine into a compact, agile package. This hyperhatch delivers 415 horsepower, all-wheel drive, and track-ready dynamics, making it a thrilling daily driver and circuit weapon.

Powertrain Excellence: The M139 Engine Revolution

At the heart of the A45 S lies the hand-built M139 2.0-liter turbocharged inline-four engine, producing 415bhp at 6750rpm and 369lb ft (500Nm) of torque between 5000-5250rpm. This output surpasses even the Audi RS3’s five-cylinder by 21bhp, cementing its status as a performance icon. Rotated 180 degrees for optimal weight distribution and equipped with twin-scroll turbocharging, the engine revs eagerly to 7200rpm, unleashing a ferocious top-end rush.

Paired with an 8-speed AMG Dual-Clutch Transmission (DCT), power flows seamlessly to all four wheels via the 4Matic+ system. This intelligent AWD setup features a multi-clutch rear differential that can send up to 100% of torque to the rear axle—and fully to one rear wheel for Drift Mode—enabling playful slides and neutral handling. The result is explosive acceleration: 0-62mph in 3.9 seconds, with real-world tests dipping to 3.78 seconds, and a top speed of 168mph (electronically limited, or 168mph in S trim).

Chassis Dynamics: Precision and Playfulness

The A45 S’s chassis transforms raw power into composed, engaging drive. Adaptive dampers in Race mode lower the ride height and stiffen settings for flat cornering, while the front axle’s torque vectoring keeps turns razor-sharp. On twisty roads, it corners flatter than rivals like the RS3, with throttle-adjustable balance that invites four-wheel drifts.

Drive modes range from Comfort (refined for cruising) to Race (feral responses), with Sport+ unlocking looser stability for spirited runs. Exhaust notes crackle and pop under hard acceleration, amplifying the drama. Despite its aggression, it cruises efficiently at 1800rpm in top gear, achieving around 31mpg on motorways.

Key Performance Specs Table

Data compiled from official specs and tests.

Design and Aerodynamics: Aggressive Yet Practical

Visually, the A45 S exudes menace with its wide stance, aggressive front splitter, large rear diffuser, and quad exhausts. Aerodynamic aids like active grille shutters and a subtle rear wing optimize downforce without compromising efficiency. Inside, the dual 10.25-inch MBUX screens dominate, offering navigation, AMG menus, and augmented reality views. Nappa leather seats with red stitching hug occupants firmly, while carbon-fiber trim adds premium flair.

Practicality shines through: 370-liter boot space accommodates luggage, and rear seats fold flat for versatility. As a five-seater hatchback measuring 4445mm long with 2729mm ground clearance (unladen), it suits urban parking and family duties.

Technology and Safety Features

Burmester audio, adaptive cruise, lane-keeping, and 360-degree cameras come standard. The AMG Track Pace app logs lap times and G-forces, turning public roads into virtual circuits. Brakes—ventilated discs front and rear—haul the 1605kg kerbweight with confidence, aided by steel brake lines for consistent feel.

Rivals Comparison: A45 S vs. Key Competitors

The A45 S faces stiff competition, but its power edge and handling prowess set it apart.

The A45 S leads in outright pace and features, though the RS3 offers unique character.

Ownership Costs and Efficiency

Priced from £63,745 in the UK (2025), first-year road tax hits £3,420 due to emissions. Fuel economy hovers at 10kmpl (approx. 28-31mpg), realistic for its output. Maintenance suits premium standards, with AMG warranties covering the powertrain. Resale holds strong thanks to desirability.

• Pros: Insane acceleration, versatile dynamics, premium interior
• Cons: Firm ride in Race mode, high running costs, road-biased Drift Mode

Driving Experience: From Street to Track

In Comfort, the A45 S glides smoothly, masking its ferocity. Sport awakens the exhaust symphony and sharpens responses. On track, it excels—neutral poise allows big slides or subtle corrections, with the rear axle pivoting precisely. Mid-range lacks RS3 snap, but the high-rev frenzy compensates, gearbox shifting lightning-fast.

Daily usability impresses: quiet cabin, light steering, and ample space. It’s a ‘firecracker’ blending supercar thrills with hatch practicality.

Mercedes-AMG Heritage in the A45 S

AMG’s engineering elevates the A-Class from premium supermini to hyperhatch legend. The second-gen A45 S refines the formula, shedding early criticisms of lacking soul for dynamic bite. Updates keep it relevant into 2025, with unchanged core specs proving enduring excellence.

Frequently Asked Questions (FAQs)

What makes the A45 S the most powerful four-cylinder car?

Its M139 engine delivers 415bhp via advanced turbo tech and rotated layout for balance.

Is the A45 S suitable for everyday driving?

Yes, Comfort mode offers refinement, efficiency, and practicality despite performance focus.

How does Drift Mode work?

4Matic+ sends full rear torque to one wheel, enabling controlled slides.

What’s the fuel economy like?

Around 31mpg combined, better on highways.

Compare A45 S to previous A45 AMG.

Newer model boosts power to 415bhp from 355bhp, adds Drift Mode and better dynamics.

Final Verdict

The Mercedes-AMG A45 S isn’t just a hot hatch—it’s a hyperhatch pinnacle, fusing brutal power, sharp handling, and luxury. Ideal for enthusiasts craving track thrills without sacrificing usability.