OAO Valvetronic Cat-Back Exhaust System for Mercedes-Benz W177 A45S / C118 CLA45S M139 2.0T

Unleash the Full Character of the AMG M139

Designed specifically for the Mercedes-AMG W177 A45S and C118 CLA45S equipped with the high-performance M139 2.0L turbocharged four-cylinder engine, the OAO Valvetronic Cat-Back Exhaust System is engineered to deliver a more aggressive exhaust character, improved exhaust flow, and complete control over your driving sound.

Combining precision exhaust engineering with electronically controlled valves, the OAO system allows drivers to switch between a refined street-driving tone and a full-volume AMG performance soundtrack.

Manufactured from premium T304 stainless steel with precision TIG welding, mandrel-bent tubing, and high-flow muffler technology, the system is engineered for durability, performance, and precise fitment.

Key Features

✓ Designed for Mercedes-AMG W177 A45S

✓ Designed for Mercedes-AMG C118 CLA45S

✓ M139 2.0L Turbocharged 4-Cylinder Engine

✓ Valvetronic Cat-Back Exhaust System

✓ Electronic Exhaust Valve Control

✓ Premium T304 Stainless Steel Construction

✓ High-Flow Performance Muffler

✓ Precision TIG Welded

✓ Mandrel-Bent Tubing

✓ Optimized Exhaust Flow

✓ Reduced Exhaust Restriction

✓ Enhanced AMG Exhaust Sound

✓ Direct-Fit Performance Design

Intelligent Valvetronic Control

Comfort Mode

Keep the valves closed for a refined and controlled exhaust tone during everyday driving.

Ideal for:

• Daily Commuting

• Highway Cruising

• Long-Distance Driving

• Residential Areas

• Reduced Exhaust Volume

• Comfortable Street Driving

The result is a more civilized exhaust experience while retaining the performance character of the AMG M139.

Sport Mode

Open the valves and unleash the aggressive personality of the A45S and CLA45S.

Experience:

• Increased Exhaust Volume

• Deeper Exhaust Tone

• Stronger Turbocharger Acoustics

• Sharper Acceleration Sound

• More Pronounced Gear-Shift Acoustics

• Enhanced High-RPM Character

• More Aggressive AMG Sound

The valve-controlled design gives you the flexibility to change the exhaust character whenever you want.

Performance-Oriented Cat-Back Design

The OAO Valvetronic Cat-Back system replaces the rear exhaust section with a high-flow performance configuration designed to improve exhaust efficiency and sound.

Potential benefits may include:

• Improved Exhaust Gas Flow

• Reduced Exhaust Backpressure

• Sharper Throttle Response

• Enhanced Turbocharger Sound

• Improved High-RPM Exhaust Flow

• Reduced Exhaust System Weight

• Stronger Exhaust Acoustics

• Excellent Compatibility with Performance Downpipes

• Optimized Performance with ECU Tuning

Actual performance gains may vary depending on vehicle configuration and supporting modifications.

Engineered for the AMG M139

The Mercedes-AMG M139 is one of the most powerful production four-cylinder engines in its class.

The OAO exhaust system is engineered around the high exhaust flow and high-temperature characteristics of the M139 platform.

Key design considerations include:

• High-Flow Exhaust Routing

• Smooth Exhaust Gas Transitions

• Optimized Tubing Diameter

• Reduced Internal Turbulence

• High-Temperature Resistance

• Performance-Oriented Muffler Design

• Electronic Valve Integration

The system is designed to complement both stock and modified M139 applications.

Enhanced M139 Sound

The M139 delivers an aggressive turbocharged performance character, and the OAO Valvetronic Exhaust amplifies that personality.

Drivers may experience:

• Deeper Cold Start

• Stronger Turbocharger Sound

• Richer 4-Cylinder Exhaust Tone

• Sharper Throttle Blips

• More Aggressive Acceleration Acoustics

• Enhanced Gear-Shift Sound

• More Pronounced Overrun Character

• Stronger High-RPM Exhaust Note

With the valves open, the system delivers a significantly more aggressive AMG-inspired soundtrack.

Premium T304 Stainless Steel Construction

Manufactured from premium T304 stainless steel to withstand the high temperatures and demanding conditions generated by the M139 engine.

Advantages include:

• Excellent Corrosion Resistance

• Superior Heat Resistance

• High Structural Strength

• Lightweight Performance Construction

• Precision TIG Welding

• CNC-Machined Connections

• Long Service Life

• Premium Surface Finish

Every OAO exhaust system is inspected before shipment to ensure consistent quality and precise fitment.

Aggressive AMG Rear-End Styling

The exhaust system is designed to complement the aggressive appearance of the A45S and CLA45S.

Optional exhaust tip finishes may include:

• Carbon Fiber Exhaust Tips

• Titanium Burnt Exhaust Tips

• Polished Stainless Steel Tips

• Dark / Matte Performance Tips

Large-diameter performance tips provide a more distinctive AMG-inspired rear-end appearance.

Vehicle Fitment

Mercedes-AMG W177 A45S

• A45S AMG

• M139 2.0L Turbocharged Engine

Mercedes-AMG C118 CLA45S

• CLA45S AMG

• M139 2.0L Turbocharged Engine

Model Years

• 2019

• 2020

• 2021

• 2022

• 2023

• 2024

• 2025+

Please verify your exact model year, drivetrain, exhaust configuration, and rear bumper design before ordering.

Package Includes

• OAO Valvetronic Cat-Back Exhaust System

• Electronic Valve Control Module

• Wireless Remote Controller

• Exhaust Installation Hardware

• Clamps / Connection Components

• Protective Packaging

Installation

Designed as a direct-fit cat-back exhaust upgrade using factory mounting locations.

No permanent cutting or welding is required for standard installation.

Professional installation is recommended to ensure proper alignment, sealing, and valve operation.

Compatible Performance Upgrades

The OAO M139 Valvetronic Cat-Back Exhaust System can be combined with:

• OAO M139 Performance Downpipe

• High-Flow Downpipe

• ECU Performance Calibration

• Performance Intake System

• Upgraded Intercooler

• Turbocharger Upgrades

• Carbon Fiber Exhaust Tips

• Titanium Exhaust Tips

A properly matched exhaust configuration can further enhance turbocharger response, exhaust flow, and overall sound character.

Important Notes

This product is designed for performance, off-road, or motorsport applications where permitted by local regulations.

Please verify local emissions and noise regulations before purchasing or installing this product.

Sound and performance characteristics may vary depending on downpipe configuration, ECU tuning, valve settings, and other vehicle modifications.

Vehicle compatibility may vary by production year and regional specification. Please confirm fitment before ordering.

Why Choose OAO Performance

OAO Performance specializes in premium exhaust systems and performance components for Mercedes-AMG, BMW M, Audi RS, Porsche, Ferrari, Lamborghini, Aston Martin, Nissan GT-R, Chevrolet Corvette, and other high-performance vehicles.

Every OAO exhaust system combines advanced engineering, premium materials, precision TIG welding, and rigorous quality control to deliver exceptional fitment, durability, and sound.

Upgrade your Mercedes-AMG W177 A45S or C118 CLA45S with the OAO Valvetronic Cat-Back Exhaust System and experience the full character of the M139 — from refined daily driving to an aggressive, high-performance AMG soundtrack at the push of a button.