Mercedes-AMG CLA 45 S
2020-2024
The CLA 45 S represents AMG's commitment to extracting maximum performance from minimal displacement. It's a technological tour de force that delivers supercar acceleration in a practical, everyday package.
Quick Take
The CLA 45 S is AMG's most powerful production four-cylinder engine vehicle, delivering supercar-level performance in a compact luxury sedan body. It features the world's most powerful series-production four-cylinder engine and AMG's sophisticated 4MATIC+ all-wheel drive system.
Best For
Key Strength
World's Most Powerful 2.0L Engine
Watch For
Complexity Breeds Reliability Issues
The Story
Heritage & Legacy
Building on AMG's tradition of high-performance compact cars, the CLA 45 S continues the lineage established by the original A 45 AMG. It represents the pinnacle of AMG's four-cylinder turbo technology development.
Design Philosophy
AMG's approach prioritizes aerodynamic efficiency and aggressive styling cues that hint at the car's serious performance intentions. The design balances everyday practicality with unmistakable AMG DNA through distinctive front splitters, side skirts, and rear diffuser elements.
The Driving Experience
Engine Character
The M139 engine delivers explosive power delivery with minimal turbo lag, thanks to its twin-scroll turbocharger and sophisticated boost management. Despite its four-cylinder configuration, it produces a surprisingly robust exhaust note and relentless acceleration that rivals much larger engines.
Chassis Dynamics
The AMG Ride Control+ suspension and AMG Dynamic Select drive modes allow the CLA 45 S to transform from comfortable daily driver to track-focused weapon. The 4MATIC+ all-wheel drive system can send up to 50% of power to the rear wheels for optimal traction and dynamic handling.
Sound Signature
The active exhaust system produces an aggressive, crackling soundtrack with pops and burbles on overrun that defies its four-cylinder origins.
Strengths & Tradeoffs
Defining Strengths
The M139 engine produces an astounding 421hp and 369 lb-ft from just 2.0 liters, making it the most powerful production four-cylinder ever. The engineering achievement is remarkable, with sophisticated cooling and a twin-scroll turbo delivering linear power delivery that feels more like a naturally aspirated V8 than a boosted four-cylinder.
Unlike many AWD systems that prioritize efficiency, the CLA 45 S uses a performance-focused setup that can send up to 50% of power to the rear wheels. The system includes drift mode and multiple drive programs that fundamentally change the car's character, making it equally capable in snow and on track.
Honest Tradeoffs
The M139 engine's extreme specific output requires premium fuel, frequent oil changes, and careful maintenance. Early examples have shown issues with turbocharger seals, fuel injectors, and the complex AWD system's electronic components. This is not a car you want to own out of warranty without a substantial maintenance fund.
The adaptive dampers struggle to balance track capability with daily comfort. Even in Comfort mode, the suspension transmits road imperfections harshly, and the low-profile tires amplify noise and impacts. The trade-off for track performance makes this challenging as a daily driver on poor roads.
Ideal Owner
Perfect for enthusiasts who want maximum performance in a practical daily driver package without the attention that comes with exotic supercars.