When it comes to performance tuning for high-end Mercedes-Benz vehicles, one of the most impactful upgrades you can make is installing an aftermarket downpipe. Whether you’re driving a thunderous Mercedes C63 W205 or a razor-sharp Mercedes A45S, replacing the restrictive factory unit with a high-flow downpipe—be it catted or catless—can deliver a massive improvement in exhaust flow, turbo spool, and overall power output. In this article, we’ll dive into the benefits, differences, and considerations when upgrading to catted or catless downpipes for the C63 W205, and explore the performance potential of the Mercedes A45S decat downpipe.

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What Is a Downpipe and Why Upgrade It?

A downpipe is the section of exhaust that connects the turbocharger to the rest of the exhaust system. It is a crucial bottleneck in turbocharged engines. Stock downpipes are often fitted with restrictive catalytic converters designed to meet emissions regulations but at the cost of performance.

Upgrading to a performance downpipe—especially in performance-tuned AMG models—releases hidden horsepower by reducing backpressure, improving turbo response, and increasing exhaust note aggression.

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Mercedes C63 W205 Catted and Catless Downpipes

The Mercedes C63 W205 is a V8 bi-turbo beast, and the stock downpipes, while adequate for daily driving, limit its full potential. There are two main types of performance downpipes for this model:

✅ Catted Downpipes

Catted downpipes retain a high-flow catalytic converter, which helps reduce harmful emissions while still significantly improving flow over stock units. These are ideal for:

• Daily drivers who want performance without triggering check engine lights.
• Passing emissions tests in regions with strict environmental laws.
• Reducing raw exhaust smells.

Catted downpipes offer a balance of power, legality, and comfort. While they don’t provide quite the same performance gains as catless options, they’re a reliable upgrade for most C63 owners.

🔥 Catless Downpipes

Catless downpipes completely remove the catalytic converter for unrestricted exhaust flow. The result?

• Maximum horsepower and torque gains.
• Enhanced turbo spool and throttle response.
• Louder, more aggressive exhaust sound.

However, this comes with trade-offs: a strong fuel smell, potential emissions test failure, and the likelihood of a CEL (check engine light) unless tuned properly. They are best suited for track cars or off-road use.

Bold Keyword Example: The mercedes c63 w205 catted and catless downpipes give enthusiasts the flexibility to choose between raw performance or balanced street legality depending on their driving needs.

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Mercedes A45S Decat Downpipe: A Game Changer

The new-generation Mercedes A45S AMG with its M139 2.0L turbocharged engine is already a record-breaking hatchback. But the factory downpipe holds it back from reaching peak output. Enter the decat downpipe—an upgrade that transforms the A45S into a full-blown performance machine.

A decat downpipe removes the catalytic converter entirely, which unlocks:

• Quicker turbo spool for lightning-fast acceleration.
• Up to 25–40 horsepower gains with tuning.
• Sharper throttle response and sporty exhaust note.

It’s a must-have for anyone looking to build a Stage 2+ A45S. However, like with catless systems, you’ll need a compatible ECU tune to avoid diagnostic errors and maximize performance safely.

Bold Keyword Example: If you’re chasing peak power and aren’t concerned with emissions, the mercedes a45s decat downpipe delivers pure, unfiltered performance that serious tuners crave.

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Final Thoughts

Whether you’re considering catted or catless downpipes for your C63 W205, or planning to unleash the full potential of your A45S with a decat downpipe, these upgrades are among the most impactful modifications you can make. Just remember:

• Catted = best for street use with moderate gains and legality.
• Catless/Decat = maximum power, aggressive tone, best suited for tuned setups.

Before upgrading, always check your local emissions laws and consult a qualified tuning shop for ECU recalibration.