Focus RS Mountune Vs AMG A45: Complete Comparison

Hyper hatches have redefined what practical family cars can achieve, blending supercar performance with everyday usability. In this detailed comparison, we pit the Ford Focus RS enhanced by the Mountune tuning kit against the Mercedes-AMG A45, two icons in the high-performance compact car segment. Both deliver over 370 horsepower from turbocharged four-cylinder engines, all-wheel drive grip, and exhilarating dynamics, but they cater to different priorities: raw value and fun versus premium refinement and outright speed.

Powertrain Breakdown: Engines That Punch Above Their Weight

The Ford Focus RS starts with a potent 2.3-liter turbocharged inline-four producing 345 horsepower and 350 lb-ft of torque in stock form. The Mountune kit, a factory-approved upgrade costing around £895 in the UK, boosts this to 370 horsepower and up to 500 Nm of torque through optimized intake, exhaust, and ECU remapping. This transformation turns the RS into a budget supercar alternative, maintaining warranty coverage while unlocking serious potential.

Mercedes counters with its hand-built 2.0-liter turbo four-cylinder in the A45, a marvel of engineering that squeezes out 375 horsepower and 475 Nm from an even smaller displacement. Paired with a seven-speed dual-clutch transmission and 4MATIC+ all-wheel drive featuring variable torque distribution up to 100 percent rear bias, it claims 0-62 mph in 4.2 seconds and a top speed of 168 mph with the limiter removed.

These figures highlight how both cars have closed the gap to sports car territory, with the Mercedes edging ahead in measured output—456 ps versus the Ford’s 326 ps in independent tests.

Straight-Line Supremacy: Drag Race Results

Acceleration is where these hatches shine, turning stoplights into launchpads. The Mercedes-AMG A45 demonstrates superior straight-line prowess, hitting 0-60 kph in 2.0 seconds compared to the Focus RS’s 2.1 seconds. By 100 kph, the gap widens: 22.1 seconds for 1000 meters at 236 kph for the A45 versus 24.2 seconds at 218 kph for the RS.

Quarter-mile times further underscore this: the A45 clocks 11.9 seconds, outpacing the Ford’s 13.1 seconds. Rolling acceleration from 80-160 kph in fourth gear favors the Mercedes at 7.0 seconds against 9.4 seconds, though the Ford holds its own in higher gears. Top speeds are close, with the A45 at 273 kph and RS at 268 kph.

• 0-60 mph: A45 3.6s vs RS 4.5s
• 0-100 mph: A45 8.7s vs RS 11.7s
• Braking 100-0 kph: A45 34m vs RS tighter but less consistent

These metrics position the A45 as the drag-strip king, benefiting from its lightning-quick DCT and advanced AWD.

Track and Handling Dynamics: Grip Meets Playfulness

Beyond brute speed, cornering ability defines hot hatches. The Focus RS Mountune employs a torque-vectoring rear differential that sends power to the outer rear wheel, enabling playful slides and drift modes—a signature Ford feature loved by enthusiasts. This setup delivers immense engagement on twisty roads, with adjustable dampers in its three-mode system balancing compliance and sharpness.

The A45’s 4MATIC+ system offers ‘Drift Mode’ for rear-wheel bias up to 80 percent, but testers note it feels more clinical, prioritizing grip over theatrics. Its adaptive dampers provide superior body control, soaking up imperfections better than the stiffer Ford, though front-end bias can lead to understeer under hard cornering. Slalom speeds are neck-and-neck at around 71 kph.

Braking distances favor the Mercedes: 100 kph stops in 32 meters versus the Ford’s 34 meters, with consistent fade resistance. Overall track scores give the A45 a 100/91 edge over the RS.

Daily Drivability and Ride Quality

Hyper hatches must excel beyond the track. The Focus RS impresses with its manual gearbox, offering precise shifts and rev-matching, paired with a surprisingly compliant ride in Normal mode. Fuel economy hovers at 9.9 L/100km, reasonable for its power.

The A45’s DCT snaps through gears seamlessly, ideal for traffic, and its interior exudes luxury with high-quality materials and digital displays. Ride quality edges ahead in Comfort mode, though it’s thirstier in tests at 6.5 L/100km combined—likely optimistic. Both handle urban duties well, but the Ford feels more approachable for spirited backroad blasts.

Interior Comfort and Practicality

Ford’s cabin is functional with Recaro sports seats gripping occupants firmly, ample rear space, and a 300-liter boot. Infotainment is straightforward but dated compared to rivals.

Mercedes elevates with Nappa leather options, ambient lighting, and a twin-screen MBUX system responsive to voice commands. Boot space matches at 370 liters expandable to 1,200, with slightly more rear legroom.

Price and Ownership Value

Here’s the game-changer: A Mountune-equipped Focus RS totals around £31,000, undercutting the A45’s £41,000 starting price by a third. Running costs favor the Ford with cheaper insurance and maintenance, though Mercedes offers a prestige badge and longer warranty options.

In used markets, RS models hold value well, amplified by tunability, while A45 depreciation reflects its premium positioning.

Real-World Road Test Insights

Drivers rave about the RS’s ‘hoot’ factor—the torque-vectoring diff induces grins through precise handling and manual involvement. The A45 counters with effortless pace and composure, feeling like a mini-AMG GT on rails, though some find it less soulful.

For track days, the A45’s superior brakes and power-to-weight (258 ps/tonne vs 225) shine. Daily, both excel, but the Ford’s lower entry point democratizes hyper hatch joy.

Pros and Cons at a Glance

• Ford Focus RS Mountune Pros: Unbeatable value, playful handling, manual fun
• Cons: Less refined, slower in straights
• Mercedes-AMG A45 Pros: Faster acceleration, premium interior, tech-loaded
• Cons: High price, clinical dynamics

Which Hyper Hatch Wins?

If budget and driving purity matter, the Mountune Focus RS steals the show as a value-packed thrill machine. For uncompromised performance and luxury, the A45 commands the crown—its speed and sophistication justify the premium for many. Ultimately, both elevate the hot hatch genre to hyper levels, ensuring no wrong choice for speed seekers.

Frequently Asked Questions (FAQs)

Is the Mountune kit worth it for the Focus RS?

Absolutely—it adds 25 hp and significant torque for under £1,000, transforming the RS while preserving warranty.

How does the A45’s Drift Mode work?

It unlocks up to 80% rear torque bias, allowing controlled slides similar to the RS’s torque vectoring.

Which has better fuel economy?

The A45 claims better figures at 6.5 L/100km, but real-world tests show the RS competitive at 9.9 L/100km.

Can these cars be daily drivers?

Yes, both offer adjustable modes for comfort, generous space, and solid economy for their power.

What’s the top speed difference?

A45 reaches 273 kph, RS 268 kph—negligible in practice.