{"product_id":"stone-exhaust-bmw-n55-f30-f32-cat-back-valvetronic-exhaust-inc-335i-435i","title":"Stone Exhaust OEM Integrated Valved Cat-Back Exhaust for BMW N55 F30\/F31\/F32\/F33\/F36 335i \u0026 435i (incl. xDrive) - Optional Valvetronic AP514\/AP514Q","description":"\u003cdiv class=\"product__description rte\"\u003e\n  \u003carticle class=\"unreset\" data-scroll-scope=\"\"\u003e\n\n    \u003ch2\u003eStone Exhaust switchable valve system for BMW N55 F30 F31 F32 F33 F36 335i and 435i\u003c\/h2\u003e\n    \u003cp\u003e\n      Give your turbo six the tone and response it deserves. This from‑catalyst rear section by Stone Exhaust brings a refined soundtrack, crisp throttle feel and OEM‑level fit on BMW 3 Series and 4 Series running the N55 engine. Designed using full chassis scanning and built with premium processes, it delivers the aggressive soundtrack you want when you press on and the calm refinement you need for the daily commute.\n    \u003c\/p\u003e\n\n    \u003ch3\u003eHighlights that set it apart\u003c\/h3\u003e\n    \u003cul\u003e\n      \u003cli\u003eFactory valve integration for seamless ECU‑controlled quiet and sport operation\u003c\/li\u003e\n      \u003cli\u003eOptional Stone Valvetronic kit for manual control via remote and OBD plug‑in\u003c\/li\u003e\n      \u003cli\u003ePrecision pipe geometry achieved through 3D data capture and reverse engineering\u003c\/li\u003e\n      \u003cli\u003e7‑axis CNC mandrel bends for smooth internal flow and minimal deformation\u003c\/li\u003e\n      \u003cli\u003eMechanised spot welding and overlapping joints for long‑term durability in high heat zones\u003c\/li\u003e\n      \u003cli\u003eTight build tolerances for true bolt‑on installation with stock mounting points\u003c\/li\u003e\n      \u003cli\u003eDeep, motorsport‑inspired note under load with low cabin resonance in cruise\u003c\/li\u003e\n    \u003c\/ul\u003e\n\n    \u003ch3\u003eHow the valve control works\u003c\/h3\u003e\n    \u003cp\u003e\n      Keep it OEM and let the car’s ECU handle the flap automatically for a factory feel, or add the Stone Valvetronic upgrade to choose quiet or loud at the touch of a button. The optional kit includes an OBD controller and remote so you can switch profiles on demand.\n    \u003c\/p\u003e\n\n    \u003ch3\u003eBuilt with serious engineering\u003c\/h3\u003e\n    \u003cul\u003e\n      \u003cli\u003eOEM system digitally modelled to replicate routing, diameter and bend radii for perfect alignment\u003c\/li\u003e\n      \u003cli\u003eUp to 98 percent roundness retained on tight bends to reduce turbulence\u003c\/li\u003e\n      \u003cli\u003eCrisscross and overlapping bead techniques increase strength at critical joints\u003c\/li\u003e\n      \u003cli\u003eConsistency from mechanical welding arms for repeatable quality unit after unit\u003c\/li\u003e\n    \u003c\/ul\u003e\n\n    \u003ch3\u003eReal‑world sound and drivability\u003c\/h3\u003e\n    \u003cp\u003e\n      Closed valves give a calm, comfortable cabin on the motorway. Open the valves and your 335i or 435i rewards you with a sharper, richer N55 growl, quick‑rev character and a confident bark on throttle without the boomy drone that ruins long trips. We have installed these systems for customers and feedback has been consistently positive for tone, refinement and daily usability.\n    \u003c\/p\u003e\n\n    \u003ch3\u003eCompatibility\u003c\/h3\u003e\n    \u003cp\u003eFor BMW models with the N55 petrol engine:\u003c\/p\u003e\n    \u003cul\u003e\n      \u003cli\u003eF30 and F31 3 Series 335i, including xDrive\u003c\/li\u003e\n      \u003cli\u003eF32, F33 and F36 4 Series 435i, including xDrive\u003c\/li\u003e\n    \u003c\/ul\u003e\n\n    \u003ch3\u003ePart numbers and tailpipe styles\u003c\/h3\u003e\n    \u003cul\u003e\n      \u003cli\u003e\n\u003cstrong\u003eAP514\u003c\/strong\u003e - Dual exit with single tailpipe. Requires original bumper.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eAP514Q\u003c\/strong\u003e - Dual exit with quad tailpipes. Requires M Sport bumper.\u003c\/li\u003e\n    \u003c\/ul\u003e\n\n    \u003ch3\u003eFitting and installation\u003c\/h3\u003e\n    \u003cp\u003e\n      Professional installation recommended. MJ Modifications in Warwickshire offers supply and fit with care and precision. Request a quote at \u003ca href=\"mailto:info@mjmodifications.co.uk\"\u003einfo@mjmodifications.co.uk\u003c\/a\u003e.\n    \u003c\/p\u003e\n\n    \u003ch3\u003eWarranty\u003c\/h3\u003e\n    \u003cp\u003eStone Exhaust 2 year warranty.\u003c\/p\u003e\n\n    \u003ch3\u003eManufacturer\u003c\/h3\u003e\n    \u003cp\u003eStone Exhaust\u003c\/p\u003e\n\n    \u003ch3\u003eSearch phrases to help you find this system\u003c\/h3\u003e\n    \u003cp\u003e\n      BMW F30 335i sports exhaust UK, BMW 335i switchable valve exhaust, BMW 435i performance system, F31 touring exhaust upgrade, F32 coupe flap exhaust, F33 convertible exhaust upgrade, F36 Gran Coupe exhaust UK, N55 stainless performance exhaust, N55 switchable flap system, BMW xDrive compatible exhaust, quad tip exhaust for BMW 435i, quiet to loud exhaust for BMW, ECU integrated valve exhaust, remote valve controller exhaust, premium mandrel bent exhaust for BMW N55, UK BMW specialist exhaust upgrade, MJ Modifications BMW exhaust fitting Warwickshire, AP514 exhaust, AP514Q quad tailpipes.\n    \u003c\/p\u003e\n\n  \u003c\/article\u003e\n\u003c\/div\u003e","brand":"Stone Exhaust","offers":[{"title":"Dual Exit with Twin Tailpipes \/ Require Original Bumper \/ Flat Cut Gloss Carbon Fiber (82mm)","offer_id":56008685584770,"sku":null,"price":2710.08,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0871\/5445\/8937\/files\/1020CG_FlatCutGlossCarbonFibre_102mm-2_300x300_b6d07d13-3e71-4782-9047-dc86155495f1.png?v=1764090705","url":"https:\/\/mjmodifications.co.uk\/products\/stone-exhaust-bmw-n55-f30-f32-cat-back-valvetronic-exhaust-inc-335i-435i","provider":"MJ Modifications","version":"1.0","type":"link"}