Stone Exhaust Mercedes-Benz CLA200/CLA250 (C117/X117, M270) Cat-Back Valvetronic Exhaust for CLA & Shooting Brake w/ Plug & Play OBDII Remote | OPF Delete Compatible | MP503S

Switchable Sports Catback for Mercedes CLA 200 and CLA 250 - C117 and X117 M270 - Remote Valve Control - Part MP503S

Transform the way your CLA sounds and drives with this premium valved catback system from Stone Exhaust. Designed specifically for the M270-powered CLA-Class coupé and Shooting Brake, it delivers a deeper tone for daily use and a fierce soundtrack at the touch of a button. If you are searching for a performance exhaust upgrade for your CLA that is refined on the motorway yet exhilarating when you want it, this is the one we recommend.

What makes it a standout upgrade

• Purpose-built for C117 and X117 models with the M270 engine including CLA 200, CLA 250, CLA 250 4MATIC and CLA 250 Sport 4MATIC
• Switchable valve system with ON, OFF and AUTO modes for quiet cruising or full-bore sound on demand
• Plug-in OBD2 controller included for quick install and instant valve control from the remote
• Refined acoustics with no intrusive cabin boom in Comfort
• One piece design with precision machine welding for strength and reliability
• 7 axis CNC bending for smooth gas flow and exceptional roundness through tight radii
• Advanced overlapping and crisscross weld techniques at high-stress joints for durability
• Developed with OEM 3D scanning, reverse engineering and in-house dyno work for sharper throttle response

Everyday civility, weekend aggression

Valves closed delivers a mature, deeper tone that is easy to live with. Open the valves and the system unleashes a race-inspired soundtrack that highlights the M270 character. In AUTO you can set a predefined RPM so the valves open automatically when you are on it and close again for relaxed cruising.

OPF compatibility

Running an OPF or GPF car? An OPF delete option can be included free of charge. This allows installation on OPF-equipped vehicles without triggering a warning light, so ECU coding to remove OPF faults is not required.

Engineered for perfect fit and performance

Stone Exhaust captures OEM geometry using 3D scanning to match factory routing and clearances. Flow is optimised by simulating pressure zones and thermal loads, while 7 axis CNC bending achieves up to 98 percent roundness with minimal outer bore wear at tight bends. The result is reduced turbulence, improved response and lasting reliability.

Tried, fitted and loved by our customers

We have installed this system on customer CLA 200 and CLA 250 builds and the feedback has been consistently excellent. Owners praise the sound quality, the instant switch from discreet to aggressive with the remote, the lack of drone at speed and the factory-level fitment.

Vehicle fitment

• Mercedes CLA 200 C117 2013+
• Mercedes CLA 250 C117 2013+
• Mercedes CLA 250 4MATIC C117 2014+
• Mercedes CLA 250 Sport 4MATIC C117 2014+
• Mercedes CLA 250 Shooting Brake X117 2015+

Part number

MP503S

Warranty

Stone Exhaust 2 year warranty.

Professional fitting

Want it installed by specialists who know these cars inside out? Book fitting with MJ Modifications in Warwickshire. Email info@mjmodifications.co.uk for a quote and availability.

Sound and media

Mercedes C117 M270 CLA 250 Stone Exhaust Sound

R&D and manufacturing detail

Stone valve control system - install overview

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