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Stone Exhaust

Stone Exhaust Valvetronic Cat-Back/Rear Section for Porsche Panamera 4S 971 2.9T V6 2016+ (440 PS) - Valved Active Sports Performance Exhaust, Switchable Flap Muffler, Remote OBD2 Control, OPF/GPF Compatible

Stone Exhaust Valvetronic Cat-Back/Rear Section for Porsche Panamera 4S 971 2.9T V6 2016+ (440 PS) - Valved Active Sports Performance Exhaust, Switchable Flap Muffler, Remote OBD2 Control, OPF/GPF Compatible

£5,099.52
£6,374.40 £5,099.52
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Valvetronic Cat-Back for Porsche 971 Panamera 4S 2.9T 440 PS

Transform the character of your Porsche with a premium active-valve rear system that delivers a richer tone, effortless control and factory-level fit. This Stone Valvetronic cat-back is a direct bolt-on for the 971 Panamera 4S 2.9 twin turbo and is the ideal upgrade if you want a deeper soundtrack on demand without sacrificing refinement for daily use. Remote operation via the OBD2 plug lets you choose quiet, loud or automatic valve behaviour at the touch of a button. If you are searching for a Panamera 4S sports exhaust, active exhaust, valved backbox, or a GPF friendly solution in the UK, this is the one we recommend and use ourselves.

We run Stone systems on our own demonstrators and many customer builds. Fitment is precise, the welds are superb, and feedback on sound quality and comfort has been consistently excellent. Valves closed it is civilised for long journeys. Valves open it sounds purposeful and sporty, with no fuss.

Highlights

  • Designed specifically for Porsche 971 Panamera 4S 2.9T 440 PS from 2016 onwards
  • Dual valve active system with three modes controlled by remote fob
  • Plug-in OBD-II controller for simple installation and instant control
  • Tuned to reduce cabin boom for relaxed motorway cruising
  • One piece layout for accurate alignment and OE-style fit
  • Developed on the dyno for responsive flow characteristics
  • Digitally scanned and reverse-engineered from the factory system
  • 7 axis CNC bending and advanced welding for strength and longevity

Switchable sound with OBD control

Choose quiet, open or auto using the supplied remote. In auto mode you can set a trigger RPM so it stays refined in town and wakes up when you want more drama. The OBD2 plug-and-play module keeps the install neat and quick, with no permanent modifications to the vehicle’s wiring.

OPF and GPF ready

Running a particulate filter equipped Panamera 4S 2.9T The system is compatible, and an OPF delete solution can be supplied on request so you can run the cat-back without warning lights. No ECU coding is required for fault removal when using the supplied solution.

Engineered for precision

Digital scan and reverse-engineering
Stone maps the OEM hardware to optimise routing, diameters and geometry. Flow and thermal behaviour are evaluated to enhance response while maintaining a perfect fit.

7 axis CNC bends
Multi-axis mandrel bending achieves exceptional roundness and accuracy, minimising restriction and helping prevent stress points at tight angles.

Structured welds
Crisscross and overlapping techniques with robotic spot welding deliver repeatable quality at high-stress joints for long-term durability.

Compatibility

  • Porsche Panamera 4S 971 2.9 twin turbo 440 PS, 2016 onwards

What is included

  • Stone Valvetronic cat-back assembly for 971 Panamera 4S 2.9T
  • Dual valve control hardware
  • Plug-and-play OBD-II control module
  • Remote control with Quiet, Open and Auto modes
  • OPF delete solution available on request

Installation and support

Professional fitting recommended. Book with MJ Modifications in Warwickshire and request a quote at info@mjmodifications.co.uk. We are happy to advise on setup, GPF compatibility and everyday usability.

Part number and warranty

Part number: QP507SQ

Warranty: Stone Exhaust 2 Year Warranty

At a glance

  • Porsche 971 4S 2.9T sports exhaust upgrade
  • Active valves with handheld remote
  • Three operating modes with OBD2 plug control
  • One piece cat-back for OEM-like fit
  • Refined cruising with a deeper tone on throttle
  • Flow optimised, reverse-engineered design
  • 7 axis CNC mandrel bends and precision welding

Media

Valvetronic system overview and installation

Sound clip – Stone Valvetronic on Porsche 971 Panamera 4S 2.9T

Gallery

Porsche 971 Panamera 4S 2.9T Stone Valvetronic Cat-Back - Angle 1

Porsche 971 Panamera 4S 2.9T Stone Valvetronic Cat-Back - Angle 2

Porsche 971 Panamera 4S 2.9T Stone Valvetronic Cat-Back - Angle 3

Porsche 971 Panamera 4S 2.9T Stone Valvetronic Cat-Back - Angle 4

Technical insights

Digital scan and reverse-engineering of Porsche Panamera 4S exhaust

7 axis CNC mandrel bending for precision exhaust manufacture

Crisscross and overlapping weld technique

Robotic direct spot welding for consistency

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