Stone Exhaust Mercedes-Benz M274 W213 Cat-Back Valvetronic Exhaust System for E250 and E300
Transform the sound and response of your Mercedes-Benz E-Class with the Stone Exhaust Cat-Back Valvetronic Exhaust System for the M274 engine. Designed specifically for the W213 E250 and E300 (2017 onwards), and developed using 3D scanning and OEM reverse engineering, this system delivers a precise OEM fit with a deeper, sportier tone, reduced drone and proven performance gains on the dyno. If you want a premium Mercedes E-Class W213 cat back exhaust upgrade that is plug and play, valve controlled and engineered to last, this is it.
This Stone Exhaust Mercedes E250 exhaust and Mercedes E300 exhaust uses the brand’s signature Valvetronic technology with a dedicated remote, giving you full control over volume and character. Enjoy quiet cruising with the valves closed or open them for an aggressive exhaust note and a sharper driving experience. With Stone’s R&D, 7 axis CNC bending and precision welding, every section is optimised for flow, strength and repeatable fitment.
Key features and benefits
- Direct fit Cat-Back Valvetronic exhaust system for Mercedes-Benz E-Class W213 and C238 E250 and E300 with the M274 engine
- Remote-controlled valves with On, Off and Auto modes for everyday comfort or sport sound on demand
- Auto mode can be set to open valves at a predefined RPM
- Plug and play OBDII controller for quick, clean installation
- One piece design with precise OEM-style fitment
- Eliminates drone commonly found on the standard exhaust system
- Dyno developed in house for performance and flow
- Mechanical welding with precision for durability and consistency
- In-house research, 3D scanning and reverse engineering for exact alignment and clearance
OPF delete option
Stone offers an OPF delete that can be included free of charge. This allows you to install the Stone Cat-Back exhaust on OPF equipped cars without triggering an error code, so coding out the OPF on the ECU is not required.
Valvetronic control, plug and play
The Stone Valvetronic system is engineered in house to maximise longevity and ease of use. With the supplied remote you can choose On, Off or Auto modes at the press of a button. Auto mode lets you define the RPM at which the valves open so you can tailor sound to your driving. The system connects via the OBDII port, making it a true plug and play upgrade that can be installed in minutes.
R&D and 3D scanning for Mercedes-Benz M274
Stone Exhaust engineers 3D scan the OEM Mercedes-Benz E-Class W213 and C238 exhaust to analyse routing, pipe diameters and bend geometry, then simulate exhaust gas flow, temperature and pressure zones to minimise restriction and maximise power. The result is a cat back exhaust that fits like factory, sits perfectly in the tunnel and clears heat shields and suspension arms just as it should.
7 axis CNC bending and precision manufacturing
Built using a state of the art 7 axis CNC bending machine, Stone achieves up to 98 percent roundness with only 25 percent outer bore wear at 180 degrees, helping prevent turbulence and weld fractures. Reverse engineering and 3D design deliver an integrally moulded pipe accuracy error under 0.025 mm for excellent flow and fit.
Advanced welding for reliability
Stone utilises crisscross and overlapping welding techniques to widen and deepen penetration at high stress areas, particularly around flanges that see extreme heat. Direct spot welding with mechanical arms increases strength and consistency for a finish that is both robust and beautifully executed.
Compatibility
Engine: M274 and M274 4Matic
Mercedes-Benz E-Class:
- W213 E250 (2017 onwards)
- W213 E300 (2017 onwards)
Also suitable for C238 applications where specified by Stone. Please check before ordering if you are unsure.
Part number
MP518AS
Installation and fitting
The Valvetronic controller is plug and play via the OBDII port and the exhaust is designed for direct fitment. For professional installation and peace of mind, we recommend booking fitting with Nforcd in Warwickshire. Request a fitting quote at Sales@nforcd.com.
Warranty
Stone Exhaust 2 Year Warranty
Photos and sound
Why buy from Nforcd
We have supplied and installed Stone Exhaust systems for Mercedes-Benz customers who wanted a refined yet sporty upgrade with everyday usability. Feedback has been consistently positive on fitment quality, sound control and drivability. If you want a Mercedes W213 E250 or E300 cat back exhaust that is quiet on the motorway and exciting on a B-road, this Valvetronic system is the perfect choice.
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