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Stone Exhaust

Stone Exhaust BMW 340i 440i B58 Valved Cat-Back (Catback) Performance Exhaust F3x F30 F31 F32 F33 F36 - Switchable/Valvetronic, OEM Valve Integration + OBD Controller, OPF/GPF Delete Friendly, Twin/Dual or Quad Tip Back Box Upgrade (AP514B58/AP514QB58)

Stone Exhaust BMW 340i 440i B58 Valved Cat-Back (Catback) Performance Exhaust F3x F30 F31 F32 F33 F36 - Switchable/Valvetronic, OEM Valve Integration + OBD Controller, OPF/GPF Delete Friendly, Twin/Dual or Quad Tip Back Box Upgrade (AP514B58/AP514QB58)

£3,256.03
£3,427.40 £3,256.03
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OEM Integrated Valve(s)
Tailpipe Finish

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.

Transform the soundtrack and response of your F3x 3 Series and 4 Series B58 with this switchable performance exhaust for 340i and 440i. Engineered for drivers who want an easy bolt-on upgrade with factory-style valve operation, rich tone and precision build quality, it’s the refined yet aggressive system our customers consistently rate as a top-tier choice. We’ve fitted this setup on multiple cars and the feedback has been superb: whisper-quiet when you want it, spine-tingling when you don’t, and perfect alignment on every install.

What makes this system stand out

  • Factory valve strategy retained for seamless quiet-to-loud transitions
  • Plug-in OBDII controller included for reliable, hassle-free valve control
  • One-piece architecture for smooth gas flow and spot-on fitment
  • Precision-formed pipework with advanced machine welding for strength and consistency
  • Developed using 3D scanning, reverse engineering and simulation for the B58 platform

OPF and GPF friendly solution included

Running a particulate filter on your F3x B58? A dedicated OPF delete solution is supplied at no extra cost, allowing installation on OPF-equipped vehicles without warning lights or ECU coding. Ideal for owners searching for a GPF workaround on 340i and 440i models.

Acoustic character you can live with

Valve closed gives you a calm, refined drive with minimal cabin intrusion. Open the valve and you unlock a sharper, motorsport-inspired note that lets the B58 sing. Daily comfort meets weekend thrills in one system.

Built with serious engineering

Each unit is digitally measured against original hardware for millimetre-accurate routing. 7-axis CNC bending targets exceptional roundness and minimises deformation on tight radii, helping reduce turbulence. Overlapping and crisscross weld techniques deliver durability where temperatures peak, and the finish looks as good as it performs.

Valve control options

The exhaust integrates with the car’s original strategy out of the box. Want manual control at your fingertips? Add the optional Stone Valvetronic System single-valve controller to switch volume levels remotely.

Fitment

BMW 3 Series

  • F30 LCI / F31 LCI 340i / 340i xDrive 2014 to 2018

BMW 4 Series

  • F32 / F32 LCI 440i / 440i xDrive 2015 to 2017
  • F33 440i 2015 to 2017 / 440i xDrive 2013 to 2017
  • F33 LCI 440i / 440i xDrive 2016 to 2018
  • F36 440i / 440i xDrive 2015 to 2017
  • F36 LCI 440i / 440i xDrive 2016 to 2018

Tailpipe styles and part numbers

  • AP514B58 - Twin outlet with dual tips - suits the original rear bumper
  • AP514QB58 - Twin outlet with quad tips - requires M Sport rear bumper

Perfect pairing for more flow

Frequently combined with B58 downpipes for a bigger performance and sound gains:

  • Stone Exhaust BMW B58 Catless Performance Downpipe (covers M140i, M240i, 440i, 540i, 740i, X5 M40i)
  • Stone Exhaust BMW B58 Eddy Catalytic Performance Downpipe (covers M140i, M240i, 440i, 540i, 740i, X5 M40i)

Match a B58 downpipe with this rear section for a sharper throttle response and deeper tone.

Why enthusiasts choose this upgrade

  • OEM-level valve integration for effortless everyday use
  • Plug-and-play installation with supplied OBDII valve controller
  • One-piece layout for optimised exhaust gas velocity
  • Machine welding for repeatable quality and long-term reliability
  • Data-driven R&D with 3D scanning and reverse engineering

Warranty

Backed by a 2 year manufacturer warranty.

Professional fitting

Want it installed by specialists who know these cars inside out? MJ Modifications offers fitting at our Warwickshire workshop. Email info@mjmodifications.co.uk for a quote and booking.

Search-friendly terms customers use

If you’re browsing for a 3 Series 340i sports exhaust, 4 Series 440i performance back box, B58 switchable system, quad outlet conversion, twin exit tips, F30 F31 F32 F33 F36 exhaust upgrade, GPF friendly exhaust solution, plug-in valve controller, F3x 340i muffler, 440i rear section, or B58 sound upgrade, this is the premium choice that delivers sound, quality and fitment.

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