{"product_id":"stone-exhaust-porsche-971-panamera-4s-2-9t-440ps-cat-back-valvetronic-exhaust-system","title":"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","description":"\u003cdiv class=\"product__description rte\"\u003e\n  \n  \u003ch2\u003eValvetronic Cat-Back for Porsche 971 Panamera 4S 2.9T 440 PS\u003c\/h2\u003e\n  \u003cp\u003eTransform 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.\u003c\/p\u003e\n  \u003cp\u003eWe 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.\u003c\/p\u003e\n  \n  \u003ch3\u003eHighlights\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eDesigned specifically for Porsche 971 Panamera 4S 2.9T 440 PS from 2016 onwards\u003c\/li\u003e\n    \u003cli\u003eDual valve active system with three modes controlled by remote fob\u003c\/li\u003e\n    \u003cli\u003ePlug-in OBD-II controller for simple installation and instant control\u003c\/li\u003e\n    \u003cli\u003eTuned to reduce cabin boom for relaxed motorway cruising\u003c\/li\u003e\n    \u003cli\u003eOne piece layout for accurate alignment and OE-style fit\u003c\/li\u003e\n    \u003cli\u003eDeveloped on the dyno for responsive flow characteristics\u003c\/li\u003e\n    \u003cli\u003eDigitally scanned and reverse-engineered from the factory system\u003c\/li\u003e\n    \u003cli\u003e7 axis CNC bending and advanced welding for strength and longevity\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003eSwitchable sound with OBD control\u003c\/h3\u003e\n  \u003cp\u003eChoose 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.\u003c\/p\u003e\n  \n  \u003ch3\u003eOPF and GPF ready\u003c\/h3\u003e\n  \u003cp\u003eRunning 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.\u003c\/p\u003e\n  \n  \u003ch3\u003eEngineered for precision\u003c\/h3\u003e\n  \u003cp\u003e\u003cstrong\u003eDigital scan and reverse-engineering\u003c\/strong\u003e\u003cbr\u003eStone maps the OEM hardware to optimise routing, diameters and geometry. Flow and thermal behaviour are evaluated to enhance response while maintaining a perfect fit.\u003c\/p\u003e\n  \u003cp\u003e\u003cstrong\u003e7 axis CNC bends\u003c\/strong\u003e\u003cbr\u003eMulti-axis mandrel bending achieves exceptional roundness and accuracy, minimising restriction and helping prevent stress points at tight angles.\u003c\/p\u003e\n  \u003cp\u003e\u003cstrong\u003eStructured welds\u003c\/strong\u003e\u003cbr\u003eCrisscross and overlapping techniques with robotic spot welding deliver repeatable quality at high-stress joints for long-term durability.\u003c\/p\u003e\n  \n  \u003ch3\u003eCompatibility\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003ePorsche Panamera 4S 971 2.9 twin turbo 440 PS, 2016 onwards\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003eWhat is included\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eStone Valvetronic cat-back assembly for 971 Panamera 4S 2.9T\u003c\/li\u003e\n    \u003cli\u003eDual valve control hardware\u003c\/li\u003e\n    \u003cli\u003ePlug-and-play OBD-II control module\u003c\/li\u003e\n    \u003cli\u003eRemote control with Quiet, Open and Auto modes\u003c\/li\u003e\n    \u003cli\u003eOPF delete solution available on request\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003eInstallation and support\u003c\/h3\u003e\n  \u003cp\u003eProfessional fitting recommended. Book with MJ Modifications in Warwickshire and request a quote at \u003ca href=\"mailto:info@mjmodifications.co.uk\"\u003einfo@mjmodifications.co.uk\u003c\/a\u003e. We are happy to advise on setup, GPF compatibility and everyday usability.\u003c\/p\u003e\n  \n  \u003ch3\u003ePart number and warranty\u003c\/h3\u003e\n  \u003cp\u003e\u003cstrong\u003ePart number:\u003c\/strong\u003e QP507SQ\u003c\/p\u003e\n  \u003cp\u003e\u003cstrong\u003eWarranty:\u003c\/strong\u003e Stone Exhaust 2 Year Warranty\u003c\/p\u003e\n  \n  \u003ch3\u003eAt a glance\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003ePorsche 971 4S 2.9T sports exhaust upgrade\u003c\/li\u003e\n    \u003cli\u003eActive valves with handheld remote\u003c\/li\u003e\n    \u003cli\u003eThree operating modes with OBD2 plug control\u003c\/li\u003e\n    \u003cli\u003eOne piece cat-back for OEM-like fit\u003c\/li\u003e\n    \u003cli\u003eRefined cruising with a deeper tone on throttle\u003c\/li\u003e\n    \u003cli\u003eFlow optimised, reverse-engineered design\u003c\/li\u003e\n    \u003cli\u003e7 axis CNC mandrel bends and precision welding\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003eMedia\u003c\/h3\u003e\n  \u003cp\u003e\u003cstrong\u003eValvetronic system overview and installation\u003c\/strong\u003e\u003c\/p\u003e\n  \u003cp\u003e\u003ciframe width=\"1195\" height=\"672\" src=\"https:\/\/www.youtube.com\/embed\/V5c4VEyO1EM\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n  \u003cp\u003e\u003cstrong\u003eSound clip – Stone Valvetronic on Porsche 971 Panamera 4S 2.9T\u003c\/strong\u003e\u003c\/p\u003e\n  \u003cp\u003e\u003ciframe width=\"1195\" height=\"672\" src=\"https:\/\/www.youtube.com\/embed\/bN8iLmUpuh4\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n  \n  \u003ch3\u003eGallery\u003c\/h3\u003e\n  \u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Stone_Exhaust_Porsche_971_Panamera_4S_2.9T_440ps_Cat-Back_Valvetronic_Exhaust_System_Stone_Exhaust_USA-1_600x600.png?v=1595328177\" alt=\"Porsche 971 Panamera 4S 2.9T Stone Valvetronic Cat-Back - Angle 1\"\u003e\u003c\/p\u003e\n  \u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Stone_Exhaust_Porsche_971_Panamera_4S_2.9T_440ps_Cat-Back_Valvetronic_Exhaust_System_Stone_Exhaust_USA-2_600x600.png?v=1595328185\" alt=\"Porsche 971 Panamera 4S 2.9T Stone Valvetronic Cat-Back - Angle 2\"\u003e\u003c\/p\u003e\n  \u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Stone_Exhaust_Porsche_971_Panamera_4S_2.9T_440ps_Cat-Back_Valvetronic_Exhaust_System_Stone_Exhaust_USA-3_600x600.png?v=1595328198\" alt=\"Porsche 971 Panamera 4S 2.9T Stone Valvetronic Cat-Back - Angle 3\"\u003e\u003c\/p\u003e\n  \u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Stone_Exhaust_Porsche_971_Panamera_4S_2.9T_440ps_Cat-Back_Valvetronic_Exhaust_System_Stone_Exhaust_USA-4_600x600.png?v=1595328210\" alt=\"Porsche 971 Panamera 4S 2.9T Stone Valvetronic Cat-Back - Angle 4\"\u003e\u003c\/p\u003e\n  \n  \u003ch3\u003eTechnical insights\u003c\/h3\u003e\n  \u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/1_9336c8b0-c9ea-4822-891c-83490f630707.jpg?v=1572705528\" alt=\"Digital scan and reverse-engineering of Porsche Panamera 4S exhaust\"\u003e\u003c\/p\u003e\n  \u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/bending.jpg?v=1572739395\" alt=\"7 axis CNC mandrel bending for precision exhaust manufacture\"\u003e\u003c\/p\u003e\n  \u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Stone_Exhaust_Art_of_Welding_-_1_1024x1024.jpg?v=1572828150\" alt=\"Crisscross and overlapping weld technique\"\u003e\u003c\/p\u003e\n  \u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0284\/6300\/5795\/files\/Stone_Exhaust_Art_of_Welding_-_2_1024x1024.jpg?v=1572828178\" alt=\"Robotic direct spot welding for consistency\"\u003e\u003c\/p\u003e\n  \n  \u003cp style=\"font-size: 0.95em; color: #333;\"\u003e\n    Search terms: Porsche Panamera 971 4S 2.9T sports exhaust, Panamera 4S active exhaust UK, valved backbox Panamera 971, remote controlled exhaust for Porsche 4S, OBD2 valve controller Panamera, GPF compatible exhaust system, OPF safe catback Panamera, 2016+ Porsche Panamera 4S exhaust upgrade, twin turbo 2.9 performance exhaust, Panamera 4S sound upgrade, switchable exhaust Porsche 971, UK Porsche tuning specialists, Stone Valvetronic Panamera 4S, cat back system for Porsche 971, premium Porsche exhaust UK.\n  \u003c\/p\u003e\n  \n\u003c\/div\u003e","brand":"Stone Exhaust","offers":[{"title":"Flat Cut Gloss Carbon Fibre (102mm)","offer_id":56006646956418,"sku":null,"price":5099.52,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0871\/5445\/8937\/files\/1020CG_FlatCutGlossCarbonFibre_102mm_1024x1024_2x_5852634a-bb06-4a04-a255-11b34578be73.webp?v=1764059672","url":"https:\/\/mjmodifications.co.uk\/products\/stone-exhaust-porsche-971-panamera-4s-2-9t-440ps-cat-back-valvetronic-exhaust-system","provider":"MJ Modifications","version":"1.0","type":"link"}