Stone Exhaust OEM Integrated Valve Cat-Back Exhaust for BMW N55 F15 X5 35i and F16 X6 35i
Upgrade your BMW X5 35i or BMW X6 35i with the Stone Exhaust OEM integrated valve cat-back exhaust system for the N55 engine. Developed via 3D scanning, reverse engineering and in-house dyno testing, this valved catback delivers OEM-perfect fitment, deeper tone, enhanced response and a premium soundtrack without unwanted cabin drone. If you’re searching for BMW X5 35i exhaust, BMW X6 35i exhaust, BMW N55 valved catback, F15 X5 exhaust or F16 X6 exhaust in the UK, this is the performance exhaust system you want.
We’ve installed this system on customer cars at Nforcd in Warwickshire and feedback has been consistently excellent: fitment is precise, the sound is refined with the valve closed and unmistakably sporty with the valve open. Choose OEM ECU control or add Stone’s Valvetronic remote control for on-demand sound at the touch of a button.
Why choose Stone Exhaust for your BMW X5 35i / X6 35i N55
- OEM integrated valve control: operates like factory, ECU opens and closes the valve automatically
- Optional Stone Valvetronic System (single valve) with remote control and plug and play OBDII controller
- Dyno-developed in-house for proven performance gains and authentic Stone signature sound
- One-piece design, precision mechanical welding and direct spot welding for strength and durability
- Eliminates the typical drone often found on stock systems
- 3D scanning and reverse engineering for 100% OEM fitment on F15 X5 35i and F16 X6 35i
- Designed for BMW N55 owners who want a premium valved cat-back exhaust system in the UK
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Part numbers
- AP522 — Dual exit with twin tailpipes. Requires original bumper.
- AP522Q — Dual exit with quad tailpipes. Requires X6M bumper.
Compatibility (N55 engine)
- BMW F15 X5 35i (2013–2018) / X5 35i xDrive (2012–2018)
- BMW F16 X6 35i (2013–2018) / X6 35i xDrive (2013–2018)
Sound and media
BMW F16 X6 35i with Stone Exhaust Eddy Catalytic Downpipe + OEM cat-back system
BMW F16 X6 35i with Stone Exhaust Eddy Catalytic Downpipe + Valvetronic cat-back system
Installed photos
Engineering that sets it apart
Stone Exhaust engineers use 3D scanning and reverse engineering of OEM components to analyse pipe diameter, routing and bend angles. Computational simulation is used to optimise exhaust gas flow, pressure zones and thermal behaviour before any metal is bent.
Built on a 7-axis CNC bending machine, Stone achieves up to 98% roundness with minimal outer-bore thinning at tight radii, reducing flow disturbance and preventing weld fracture. Accuracy is held to within 0.025 mm for an integrally moulded, high-precision exhaust path.
Crisscross and overlapping welding techniques increase penetration and joint width at high-heat zones, while direct spot welding by mechanical arms delivers exceptional strength and repeatable quality. The result is a durable, beautifully made performance exhaust for your BMW N55.
Fitting and support
Professional fitting available at Nforcd in Warwickshire. For a fitting quote or to discuss OEM valve integration and the optional Stone Valvetronic remote system, email Sales@nforcd.com.
Warranty
Stone Exhaust 2-year warranty.
Manufactured by
Stone Exhaust
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