Stone Exhaust BMW N55 F25 F26 Cat-Back Valvetronic Exhaust — X3 35i xDrive, X4 35i xDrive, X4 M40i xDrive
Transform the sound and response of your BMW N55 with the Stone Exhaust Cat-Back Valvetronic Exhaust. Perfect for BMW F25 X3 35i xDrive and BMW F26 X4 35i xDrive and X4 M40i xDrive owners who want a premium valved cat-back exhaust that delivers performance, quality and everyday refinement. Developed with 3D scanning, reverse engineering and in-house dyno testing, this Stone Exhaust system offers OEM-level fitment, a deep performance tone and reduced drone for comfortable motorway cruising.
If you are searching for BMW N55 cat-back exhaust, BMW X3 35i exhaust, BMW X4 35i exhaust, X4 M40i exhaust, F25 exhaust upgrade, F26 exhaust upgrade, valvetronic exhaust, valved exhaust for BMW, BMW N55 performance exhaust UK or Stone Exhaust UK, this is the system you want on your xDrive.
Compatible BMW Models — N55
- BMW F25 X3 35i xDrive
- BMW F26 X4 35i xDrive
- BMW F26 X4 M40i xDrive
Why choose the Stone Valvetronic Cat-Back for your BMW N55
- Valved performance cat-back exhaust for BMW N55 with remote control
- Deep, aggressive exhaust note on throttle — refined and drone-reduced at cruise
- OBDII plug and play controller with ON, OFF and AUTO valve modes
- AUTO mode opens the valves at a predefined RPM for the best of both worlds
- 3D scanned and reverse engineered for OEM fitment and optimal flow path
- In-house dyno developed to enhance performance and throttle response
- Precision mechanical welding and one piece sections where applicable
- 7 axis CNC bending for accuracy, flow and consistency
Valvetronic control — have it loud when you want it, quiet when you need it
- ON — valves open for maximum sound and flow
- OFF — valves closed for neighbour-friendly starts and long journeys
- AUTO — set a custom RPM for automatic valve opening
- Simple installation via OBDII — truly plug and play
Engineering that makes a difference
- 3D scanning and CAD development for perfect BMW F25 and F26 fit
- Flow simulation used during R&D to optimise pipe diameter, routing and bends
- CNC bending maintains roundness and reduces turbulence for smoother exhaust flow
- Advanced welding techniques for strength and durability at high temperatures
Options and part numbers
- AP531S — Dual exit with twin tailpipes — requires M40i bumper
- AP531BSQ — Dual exit with quad tailpipes — requires M40i bumper
Fitment and installation
- Direct fit, OEM-style mounting points for F25 X3 and F26 X4 platforms
- OBDII Valvetronic controller installs in minutes
- Professional fitting recommended for perfect alignment, especially with bumper and tailpipe options
Want it fitted by experts who know these cars inside out? Nforcd offers installation in Warwickshire. Request a fitting quote: Sales@nforcd.com.
Proven by enthusiasts
We have supplied and fitted Stone Exhaust systems to BMW X3 and X4 N55 owners and the feedback has been excellent. Customers love the premium tone, the no-drone cruising and the ability to switch sound on demand. This is a proper upgrade for anyone searching for the best BMW X3 35i exhaust, BMW X4 M40i exhaust or N55 valved cat-back in the UK.
Warranty
Stone Exhaust 2 year warranty.
Brand
Stone Exhaust
Watch and listen
Stone Valvetronic System Installation
BMW X4 35i catless downpipe sound with Stone system
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