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Stone Exhaust

Stone Valved Cat-Back/Catback Exhaust for BMW X3 G01 & X4 G02 30i xDrive (B48/B46 2.0T) - Active Valve/Valvetronic Flap-Controlled Sports Performance Exhaust, OPF/GPF/PPF Compatible, Bolt-On No-Drone Upgrade

Stone Valved Cat-Back/Catback Exhaust for BMW X3 G01 & X4 G02 30i xDrive (B48/B46 2.0T) - Active Valve/Valvetronic Flap-Controlled Sports Performance Exhaust, OPF/GPF/PPF Compatible, Bolt-On No-Drone Upgrade

£2,427.84
£3,034.80 £2,427.84
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Exhaust Valve System
Tailpipe Finish
Engine

Heads-up on cancellations & returns: if you cancel an order or return an item, you won't get back 100% of what you paid. We apply a 10% restocking fee, the outbound shipping is non-refundable, and we have to pass on Shopify / PayPal payment processing fees; these aren't returned to us when we refund you. International orders also lose on exchange-rate spread in both directions. If the original packaging is damaged or missing, a reboxing charge applies. For international orders specifically, if you refuse to pay our shipping invoice or supply a prepaid label after placing the order, the same deductions apply. We're upfront about this — please be sure of your purchase before ordering.

Switchable sports system for BMW G01 X3 30i xDrive and G02 X4 30i xDrive

Transform the character of your 2.0 turbo BMW with this valve-controlled centre and rear section, purpose-built for the B48 and B46 engines. Expect a deeper, richer soundtrack on demand, crisp throttle response and a precision fit that mirrors factory mounting points. Developed through 3D scanning, reverse engineering and in-house dyno work, it combines OEM-style integration with a true performance feel.

Key advantages

  • Factory-style valve logic retained for everyday refinement and open-valve excitement when you want it
  • Optional Stone Valvetronic remote kit available for manual sound control via a handheld controller
  • Accurate fitment thanks to detailed 3D data capture and CAD-driven development
  • In-house dyno tested for sharper response and a more engaging drive
  • Tuned to minimise cabin drone compared to the standard system
  • One-piece architecture with high precision mechanical welding for strength
  • 7-axis CNC bending for smooth internal flow and durability at tight radii
  • Plug and play OBDII controller compatibility when pairing with the Valvetronic option

How it sounds and feels

Valves closed delivers a refined tone for commuting and long motorway runs. Open the valves and you get a louder, crisper, motorsport-inspired note with pronounced upshift cracks and a fuller midrange. It is civilised when cruising, then genuinely exciting on B-roads with a noticeable lift in responsiveness.

OPF and GPF friendly options

Running a vehicle with a particulate filter fitted from factory. An OPF solution is available on request at no extra cost to allow installation without dashboard errors. No ECU coding required to clear OPF faults. For road use, please check local regulations.

Engineering that sets it apart

  • 3D scanning and reverse engineering for OEM-style hangers, flanges and clearances
  • Flow-optimised routing to reduce restriction and promote turbo spool
  • 7-axis CNC bending to maintain cross-sectional integrity through bends
  • Crisscross and overlapping weld techniques at high-stress areas for longevity
  • Direct spot welding by mechanical welding arms for repeatable precision

Fitment

Compatible with the following petrol models:

  • G01 X3 30i xDrive 2017 onward
  • G02 X4 30i xDrive 2017 onward

Real-world feedback

We have installed these systems on customer cars and our own builds. The verdict is consistently positive. Excellent fit, high quality welds, proper switchable sound and no motorway drone. A brilliant upgrade for anyone seeking a confident, sporty tone with day-to-day comfort.

Video

BMW G02 X4 30i xDrive B48 shown with catless downpipe and Stone Valvetronic cat back

Installed photos

BMW G02 X4 30i xDrive sports exhaust installed - dual exit with twin tips
BMW G02 X4 30i xDrive rear section upgrade installed
BMW X4 30i switchable exhaust detail - valve housing and pipework
BMW G02 X4 underside - performance centre and rear section routing
Twin tailpipe finishers - BMW B48 2.0T switchable sports exhaust

Technical development

Engineers capture pipe diameter, routing and bend angles then simulate gas flow, heat load and pressure zones prior to production. The result is a precision system for G01 and G02 platforms that looks factory, fits perfectly and delivers a more engaging drive.

R and D and 3D scanning for accurate fitment
7-axis CNC bending for smooth flow
Welding quality close-up
Direct spot welding for repeatability

Fitting and support

Professional installation available at MJ Modifications in Warwickshire. Request a fitting quote at info@mjmodifications.co.uk. We are happy to help with guidance on G01 and G02 valve control setup, OPF solutions and general fitment.

Warranty

Stone Exhaust 2 year warranty.

Part numbers

  • AP543B for B48 engine
  • AP543NB for B46 engine

Search-friendly terms

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