Stone Exhaust Mercedes-Benz C63S AMG (M177) Cat-Back Valvetronic Exhaust System – W205 C205 S205 A205 – Plug & Play OBDII Valve Control, Drone-Free Performance – 2014+ – MP514S

Stone Exhaust C63 S W205 Active Valve Catback - MP514S

Transform the soundtrack and response of your AMG with the Stone Exhaust switchable valve catback for the M177 twin turbo V8. This premium rear system unlocks a richer, deeper tone with the flaps open and a refined, civilised note with them closed, all while keeping motorway cruising free from unwanted resonance. It is a direct bolt-on upgrade with OEM-level fit, engineered for the C-Class saloon, estate, coupe and cabriolet from 2014 onwards.

We have installed this system for customers in our own workshop and the feedback has been outstanding for sound quality, drivability and finish. If you are searching for a C63 S valved exhaust, remote controlled catback, W205 performance back box or M177 active exhaust upgrade, this is the one to choose.

Why enthusiasts choose this setup

• Active valve catback for on-demand loud or quiet operation
• OBD2 plug-in control module with handheld remote - Open, Closed and Auto modes
• No cabin boom at constant speeds for relaxed long-distance driving
• Single piece layout for smooth flow and simple installation
• 3D scanned and reverse engineered for factory-grade fit on W205, C205, S205 and A205
• Precision CNC pipe bending and advanced overlapping welds for durability
• In-house dyno validated for performance and a crisp, motorsport-inspired note

Switchable sound, anytime

The Stone active valve system lets you tailor the exhaust character in seconds. Use the included remote to choose Open for maximum drama, Closed for discreet neighbourhood starts or Auto to let the controller manage valve position by engine speed. The module plugs into the OBD2 port, so there is no cutting or splicing and setup is quick.

OPF and GPF support

Running a later car with a particulate filter? Stone provides an OPF solution so OPF-equipped models can run this catback without warning lights. No coding required.

Engineering highlights

• OEM system 3D scanned then re-created for exact routing and clearance
• 7-axis CNC bending for consistent tube geometry and smooth gas speed
• Machine welded with crisscross and overlapping techniques for strength in high heat zones
• Tight manufacturing tolerances for repeatable fitment

Real results from our workshop

After multiple installs, we can confirm the fit is spot on, the valves operate seamlessly and the tone is addictive with the valves open yet calm with them shut. Our customers love the quality, the finish and the way it transforms the V8 character.

Fitment

Engine: AMG M177 bi-turbo V8

Body: W205 C-Class saloon, S205 estate, C205 coupe, A205 cabriolet

Transmissions: 7G and 9G

• C63 S 2014 onwards - saloon
• C63 S 2014 onwards - estate
• C63 S 2014 onwards - coupe
• C63 S 2014 onwards - cabriolet

Recommended pairing

For the ultimate AMG soundtrack and response, combine with Stone high-flow downpipes.

Professional fitting

Want it installed by experts? Book fitting with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk.

Part number

MP514S

Warranty

Stone Exhaust 2-year warranty.

R&D and manufacturing

Installation video

Sound demo

Search terms buyers use

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