Upgrading downpipes has become one of the most effective performance mods for AMG owners who want serious gains without going too deep into engine internals. Whether you’re driving a roaring Mercedes C63 W205 or the sharp, turbocharged Mercedes A45s, high-flow downpipes can completely transform how your car breathes, accelerates, and sounds. In this guide, we’ll break down everything you need to know about mercedes c63 w205 catted and catless downpipes and mercedes a45s decat downpipe, helping you understand what makes these upgrades popular among enthusiasts.
Why Downpipes Matter on AMG Engines
Both the C63 and A45s rely heavily on turbocharging to deliver their signature punch. Turbos generate incredible power, but only if exhaust gases can exit the engine freely. Stock downpipes are restrictive because of their dense catalytic converters, which are designed for emissions compliance rather than performance.
Upgrading to high-flow catted or catless downpipes reduces backpressure, allowing the turbo to spool more quickly. The result? Faster acceleration, sharper throttle response, and a richer, more aggressive exhaust tone.
C63 W205: Catted vs. Catless Downpipes
The twin-turbo V8 in the W205 C63 responds exceptionally well to airflow improvements. Owners typically choose between catted and catless downpipes depending on their goals.
Catted Downpipes
Catted downpipes include high-flow catalytic converters, giving you a balance between power and daily drivability. You get:
- Noticeably improved turbo spool
- Deeper, cleaner exhaust tone
- Better low-end torque
- Fewer potential issues with emissions checks
They’re perfect for drivers who want performance gains but still want to keep the setup moderately street-friendly.
Catless Downpipes
Catless versions take things to the next level by eliminating the catalytic mercedes a45s decat downpipe converters altogether. This gives the C63 maximum exhaust flow, which translates to:
- Stronger gains in horsepower and torque
- The raw, aggressive AMG soundtrack many enthusiasts love
- More intense turbo whistle and pops
The trade-off is higher exhaust odor and a louder overall experience. Catless downpipes are generally ideal for track-focused builds or those chasing maximum output when paired with a tune.
Mercedes A45s Decat Downpipe: Unlocking the Hot-Hatch’s True Potential
The A45s, with its hand-built M139 2.0L turbo engine, is already the world’s most powerful four-cylinder production engine. Still, it leaves a lot of potential on the table due to restrictive factory components.
A decat downpipe upgrade removes the catalytic converter entirely, letting the turbocharger push out exhaust gases rapidly. Benefits include:
- Better throttle response
- Noticeable horsepower and torque improvements
- Loud, sporty, and more aggressive exhaust tone
- Enhanced turbo spool and crackles
This upgrade is especially popular with enthusiasts who want their A45s to feel more alive without diving into engine modifications.
Pairing Downpipes With Tuning
Downpipes alone add performance, but pairing them with an ECU tune unleashes the full potential. A proper tune will optimize ignition timing, turbo pressure, and fueling to complement the increased airflow. Both the C63 and A45s see the biggest power gains when downpipes and tuning work together.
What to Consider Before Upgrading
Before you pick your ideal downpipe setup, keep a few things in mind:
- Sound levels: Catless and decat options are loud — make sure that suits your driving style and local regulations.
- Emissions compliance: Catted downpipes are usually better for street-legal setups.
- Heat management: High-performance downpipes can raise exhaust temperatures, so heat wrapping or ceramic-coating is often helpful.
- Professional installation: To avoid sensors or fitment issues, expert installation is highly recommended.
Final Thoughts
Whether you’re chasing deeper sound, stronger acceleration, or better turbo performance, upgrading downpipes on your Mercedes AMG is one of the most rewarding mods you can do. The C63 W205 benefits massively from both catted and catless options, while the A45s becomes a whole new machine with a decat downpipe. With the right setup, you unlock the true personality behind these performance icons — sharper, louder, and far more exciting to drive.
