Mercedes-AMG Performance Exhaust Systems and Downpipe Upgrades

Mercedes-AMG Performance Exhaust Systems & Downpipe Upgrades

Mercedes-AMG Performance Exhaust Systems

Unleash the full power and sound of your Mercedes-AMG with our performance exhaust system and downpipe upgrade service in Slough. Designed for models such as the C63, E63, A45, G63, and GT AMG, our upgrades deliver more horsepower, improved throttle response, and an aggressive exhaust note that matches the AMG’s racing pedigree.

We supply and fit premium exhaust systems from Milltek, Capristo, Quicksilver, and Scorpion, as well as custom-built exhausts tailored to your AMG. From valve-controlled systems for switchable sound, to high-flow downpipes and decat options, every upgrade is engineered for performance, precision, and reliability.

Based in Slough, we are trusted by AMG owners across Berkshire, London, and the UK who want specialist fitting, premium materials, and performance exhaust modifications that transform the driving experience.

Why Choose Onyx Performance?

As Seen on Carwow

We’ve been proudly featured on Carwow – a testament to the quality, professionalism, and performance-focused results that set us apart. Watch our feature here to see us in action.

Expertise You Can Trust

With years of experience and deep technical knowledge, our team understands performance vehicles inside and out – from custom remaps to high-end servicing.

Advanced Workshop & Tools

We operate from a state-of-the-art facility in Slough, equipped with cutting-edge diagnostics, dyno testing, and industry-leading tools for accurate, high-quality work.

Tailored Solutions for Every Vehicle

We don’t believe in one-size-fits-all. Every car gets a bespoke approach, ensuring the best results whether it’s a remap, upgrade, or routine service.

Trusted Nationwide

Performance enthusiasts from across the UK come to Onyx because they know they’ll receive premium-quality workmanship, careful attention to detail, and honest advice.

Complete Care, All in One Place

From tuning and servicing to tyres, trackers, and immobilisers – we offer a full suite of services under one roof, all with a strong focus on safety, reliability, and top-tier customer support.

Customer Reviews

    
 
 
       Posted on Google  
   
   Mark Wiltshire 
 
 
 
 Trustindex verifies that the original source of the review is Google. Professional yet friendly, very helpful would recommend 👍
  
 
      Posted on Google  
   
   Paul Forrester 
 
 
 
 Trustindex verifies that the original source of the review is Google. Nice refurbishment of my alloys
  
 
      Posted on Google  
   
   Noel Kerins 
 
 
 
 Trustindex verifies that the original source of the review is Google. Excellent service, great quality job on 2 of my black alloys. They also did my father & husbands cars too. Great value for money and a special thanks to Ben.
  
 
      Posted on Google  
   
   Jamie Taylor 
 
 
 
 Trustindex verifies that the original source of the review is Google. Had my golf R mapped and tuned to stage 2 very impressed with the work they done Ben and Sam great guys very friendly and very professional would recommend 👍🏻
  
 
      Posted on Google  
   
   DSK 
 
 
 
 Trustindex verifies that the original source of the review is Google. Brought my Audi S3 in for a Stage 3 tune with a bigger turbo and full supporting mods. Things didn’t start smoothly — the Falcon turbo I had fitted from eBay turned out to be faulty and smoked heavily on the dyno.Instead of rushing the job or giving me attitude, they helped me swap it out for a proper Garrett PowerMax and carried on professionally. Then I ran into fueling problems caused by another low‑quality eBay part, and again they took their time, diagnosed the issue properly, fixed it, and made sure everything was right before continuing.After all the setbacks, they still mapped the car, spent a lot of time on it, and didn’t charge me anywhere near what the work was worth.They showed patience, honesty, and real skill. Very happy with the service and the way they looked after me.
  
 
      Posted on Google  
   
   randip 
 
 
 
 Trustindex verifies that the original source of the review is Google. Highly recommended. Fitted my catless downpipe and full exhaust on my Audi RS7. The sound is amazing!

The staff were very friendly and kept me updated at every step of the process
  
 
      Posted on Google  
   
   Dan Simmonds 
 
 
 
 Trustindex verifies that the original source of the review is Google. This is the second time I have used Onyx Performance first time for wheel refurbishment and last time for remap and i would use their services again in the future without a doubt. They are very knowledgeable about what they specialise in, they are polite and you can see they care not only about what their customers want to do but also about what they can offer the customer. Thanks to the OP team.
  
 
      Posted on Google  
   
   Taranjit Lehal 
 
 
 
 Trustindex verifies that the original source of the review is Google. Took my Mercedes C200 to Onyx performance for a stage 1 remap, my car is much quicker and throttle response is much better than before the remap. They also advise you about power and gains and the maps are tailored for your specific car and model, no stress on engine or gearbox. Thank Onyx , Brilliant work.
  
 
      Posted on Google  
   
   Carlos fernandez 
 
 
 
 Trustindex verifies that the original source of the review is Google. Absolutely fantastic service friendly customer service will definitely be going back for further modifications 5 star service do not go anywhere else other than onyx😎🙏🏼
  
 
      Posted on Google  
   
   Aurimas Gercas 
 
 
 
 Trustindex verifies that the original source of the review is Google. Great service, recommend.

Upgrade Your Mercedes-AMG Exhaust in Slough

Transform your AMG with a performance exhaust system or downpipe upgrade, fitted by experienced specialists. Whether you want a deeper road presence, a switchable valvetronic system, or a track-focused downpipe for maximum power, we provide tailored solutions and precision fitting. Contact us today for your Mercedes-AMG exhaust upgrade in Slough or nationwide.

5-Star Google Reviews

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Why Choose Onyx Performance for Servicing?

Experts in Performance Cars

We know how to properly care for performance, modified, and luxury vehicles. Our team has the skills and experience to handle specialist requirements confidently.

Correct Service Schedules

Every service follows the exact schedule recommended by your vehicle’s manufacturer, helping maintain performance and protect your warranty.

Quality or OEM Parts

We only use high-quality aftermarket or original manufacturer parts, ensuring long-lasting reliability and top-level performance.

Full Vehicle Inspection

Our service goes beyond just changing oil. We inspect all key systems to keep your car safe, smooth, and road-ready.

Honest Advice, No Surprises

With transparent pricing and expert recommendations, you’ll always know what your car needs – no upselling, no hidden fees.

Fast, Trusted & Tracked

We offer quick turnaround, maintain service records, and send reminders – that’s why customers travel to us from across the UK.

Frequently Asked Questions

Do you provide exhaust upgrades for all AMG models?

Yes — we work on the full AMG line-up, including the C63, E63, A45, CLA45, G63, GT AMG, and more.

What are the benefits of upgrading my AMG exhaust system?

You’ll enjoy increased power, improved airflow, reduced weight, sharper throttle response, and a more aggressive exhaust tone.

Do you fit downpipes and decat systems for AMG models?

Yes — we install high-flow sports cats, decat downpipes, and GPF/OPF deletes for AMGs, designed to maximise sound and performance (track use only).

Can you fit valvetronic/switchable exhaust systems?

Absolutely — we install valve-controlled systems that allow you to switch between refined daily driving tones and track-inspired aggression at the push of a button.

Are AMG exhaust upgrades road legal in the UK?

Many performance exhaust systems are road legal and MOT-compliant, while decat downpipes and GPF deletes are for off-road/track use only. We’ll guide you on the best setup for your needs.

Do you offer custom exhaust fabrication for AMGs?

Yes — our bespoke fabrication service allows us to build a one-of-a-kind exhaust system tailored to your AMG’s performance goals and desired sound profile.

Get a quick quote

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