Stone Exhaust Valvetronic Cat-Back Exhaust for Mercedes-Benz E-Class W213/C238 (E250, E300) M274 | Remote Valve Control OBDII Plug & Play | 2017+ | No-Drone Performance Exhaust | OPF-Delete Ready | MP518AS

Stone Exhaust MP518AS switchable catback for Mercedes E-Class E250 and E300 M274

Give your E-Class 2.0 turbo a richer tone and sharper response with Stone’s valve-controlled rear system. Developed for the W213 Saloon and suitable C238 Coupe applications from 2017 onwards, this premium upgrade adds wireless sound control, refined motorway manners with minimal cabin resonance and a truly OEM-like fit. It plugs in at the diagnostic port for quick setup and transforms everyday driving with the press of a button.

Why enthusiasts choose this system

• Valve-controlled catback with wireless key fob for quiet, loud or automatic modes
• OBD plug-in controller for a clean, no-splice installation
• CAD-developed from full digital scans of the factory layout for perfect routing and tip alignment
• In-house dyno validation for optimised gas flow and throttle response
• Minimal interior resonance for relaxed cruising yet a purposeful note on throttle
• Single-section layout for accurate, repeatable fitment
• Multi-axis CNC tube forming for excellent roundness and consistent bends
• Robotic spot-welding with hand-finished seams in high-heat areas for durability
• OPF solution available at no extra cost to prevent warning lights on OPF-equipped vehicles
• Backed by a 2 year manufacturer warranty

Three sound modes, one perfect daily

Use the supplied remote to swap between discreet cruising and a more aggressive soundtrack. Choose closed for early starts, open for weekend blasts, or set Auto to open the valves at a user-defined engine speed. The result is a calm cabin on the motorway and a deeper, sportier character when you want it.

Engineered for the M274

Stone digitally maps the OE assembly, then models pressure, temperature and flow to minimise restriction. Precision tube forming maintains roundness through tight bends, while tolerances are held down to fractions of a millimetre for a factory-style fit under the car. Reinforced welds around flanges and stress points help the system stay tight and rattle-free long term.

Compatibility

Engine: 2.0 turbo petrol M274, including 4Matic variants

Models:

• Mercedes-Benz E-Class W213 E250 — 2017 onward
• Mercedes-Benz E-Class W213 E300 — 2017 onward

Also suitable for selected C238 Coupe applications where specified by Stone. If unsure, contact us before ordering.

Part number

MP518AS

OPF solution included

Running a petrol particulate filter. Stone supplies an OPF-ready setup at no additional cost to prevent fault codes, meaning no ECU coding is required for fitment on OPF-equipped cars.

Installation

This is a direct replacement from the catalytic converter back with a simple plug-in controller at the OBD port. For a seamless result, book professional fitting with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk.

What our customers say

We have installed this kit in-house and feedback has been consistently positive. Owners love the deep tone with valves open, the calm cabin at motorway speeds and the quality of the fit and finish.

Popular search terms

Mercedes E-Class W213 performance exhaust, E250 sports exhaust system, E300 switchable exhaust, M274 2.0T exhaust upgrade, remote valve exhaust Mercedes, wireless valve controller E-Class, OBD plug-in exhaust controller, resonance-free exhaust W213, E-Class saloon catback, C238 coupe exhaust system, E-Class 2.0 turbo exhaust upgrade, back box upgrade Mercedes, mid-pipe system E250, valve-operated exhaust E300, quiet to loud exhaust Mercedes, OPF solution Mercedes petrol particulate filter, UK exhaust fitting Warwickshire, Stone Exhaust MP518AS UK, Mercedes E-Class switchable backbox, plug-in valve controller Mercedes.