Stone Exhaust Cat-Back Valvetronic Valved Exhaust System for Mercedes-Benz C-Class W205 S205 C205 (M274/M264) – C200 C250 C300 | MP505S

Stone MP505S Switchable Catback Exhaust for Mercedes C Class 205 Chassis 2.0T Petrol - Saloon, Estate and Coupé

Unlock a richer sound, sharper throttle response and everyday refinement with the Stone MP505S valve-controlled catback for the Mercedes C Class 2.0 turbo. Designed for the 205 platform across saloon, S205 estate and C205 coupé, this switchable rear section gives you quiet cruising and a motorsport-inspired bark at the touch of a button. If you are hunting for a C Class sports exhaust upgrade in the UK, a C300 flap exhaust, a C200 performance system or a C250 switchable back box, this is the premium choice our customers ask for.

We have fitted and run this system at MJ Modifications and owner feedback has been outstanding. The tone is deeper without harshness, motorway drone is significantly reduced, and the build quality is exceptional. Stone’s manufacturing is second to none, so you get OEM-style fitment with a genuine performance feel.

Key benefits

• Switchable valves for a dual-personality soundtrack - quiet when you want, aggressive when you need
• Wireless remote with ON, OFF and AUTO modes for instant control
• Plug-in OBD controller - no complex wiring, neat and reversible
• Refined acoustics with reduced cabin boom for relaxed commuting and long journeys
• Optimised flow path for improved response on the 2.0T petrol engine
• 3D-scanned development for factory-style alignment and easy installation
• Precision bending and high-strength welds for durability and consistent quality

How the valve control works

Choose the sound to suit your drive. Use the remote to open or close the flaps instantly, or select AUTO to let the system open the valves by rpm and load. The controller connects to the OBD port for a clean plug-and-play installation that can be removed at any time.

OPF-GPF solution included

For models equipped with a particulate filter, Stone provides an OPF-GPF option at no extra cost to maintain compatibility without error messages. No ECU coding required. Always check local regulations before road use.

Engineered to perform and built to last

Stone begins each application with full 3D scanning of the factory system to replicate hangers, clearances and angles precisely. Development includes flow simulation and dyno validation to fine-tune back pressure and sound. A 7-axis CNC bender keeps pipe roundness to maximise gas velocity, while advanced criss-cross and overlapping weld techniques reinforce high-heat joints. The result is consistent quality, strong weld penetration and a premium finish you can trust.

Vehicle fitment - Mercedes C Class 2.0T petrol

• 205 series saloon - C200, C250, C300 including 4MATIC
• S205 estate - C200, C250 and related 7G-TRONIC and 9G-TRONIC variants
• C205 coupé - C200, C250, C300 including 4MATIC
• Suitable for M274 and M264 2.0-litre turbo engines from 2014 onwards

Why choose Stone for your C Class upgrade

• OEM-like fit with performance sound
• One-piece precision-bent sections to aid flow and fitment
• Reduced resonance for comfortable daily driving
• Proven reliability from a brand trusted by enthusiasts worldwide

Fitting and installation

Professional installation recommended. For expert fitting, contact MJ Modifications in Warwickshire for a quote: info@mjmodifications.co.uk.

Part number and warranty

Part Number: MP505S

Manufacturer: Stone Exhaust

Warranty: 2 Year Stone Exhaust Warranty

Photos

Valve control overview

R&D and manufacturing

Sound and installation videos

Mercedes C300 2.0T with Stone catback - sound clip

Stone valve system - install overview

Search terms customers use

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