{"product_id":"stone-exhaust-bmw-b48e-f40-m135i-xdrive-cat-back-valvetronic-exhaust-system","title":"Stone Exhaust BMW M135i xDrive F40 \u0026 M235i xDrive F44 B48E Valved Valvetronic Cat-Back\/GPF-Back Performance Exhaust | Switchable OBD2 Plug \u0026 Play Remote | OPF\/GPF Solution | 1 Series \u0026 2 Series Gran Coupe Sports Catback | No Drone","description":"\u003cdiv class=\"product__description rte\"\u003e\n  \n  \u003ch2\u003eStone Valvetronic system for BMW F40 M135i xDrive and F44 M235i xDrive - B48E platform\u003c\/h2\u003e\n  \n  \u003cp\u003e\n    Give your BMW 1 Series M135i xDrive F40 or BMW 2 Series Gran Coupe M235i xDrive F44 the soundtrack and response it deserves with the Stone switchable rear section. Purpose built for the B48E engine cars, this premium catback upgrade delivers a rich, motorsport-inspired tone, tangible performance gains verified on Stone’s in-house dyno, and a perfect, OEM-style fit achieved through precise 3D scanning and reverse engineering.\n  \u003c\/p\u003e\n  \n  \u003cp\u003e\n    We run this hardware on our own builds and have fitted it for many happy customers. Feedback is consistent - outstanding sound with the valves open, refined and calm with them closed, easy control through the plug-in OBD module, and no intrusive motorway drone. If you are hunting for a high quality, valve-controlled sports system for your M135i or M235i, this is the one to choose.\n  \u003c\/p\u003e\n  \n  \u003ch3\u003eKey reasons to choose this Stone system\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eVehicle specific design for BMW F40 M135i xDrive and F44 M235i xDrive cars using the B48E engine\u003c\/li\u003e\n    \u003cli\u003eDual valve, switchable sound control with remote - ON, OFF and AUTO modes\u003c\/li\u003e\n    \u003cli\u003eOBDII plug-in controller for quick installation and simple valve management\u003c\/li\u003e\n    \u003cli\u003eDeveloped to remove the cabin boom common with the factory setup for relaxed cruising\u003c\/li\u003e\n    \u003cli\u003eOne-piece layout with precision machine welding for strength and longevity\u003c\/li\u003e\n    \u003cli\u003e3D scanned and reverse engineered for true direct-fit installation\u003c\/li\u003e\n    \u003cli\u003eDyno tested by Stone for proven performance improvement\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003eSwitchable valves - quiet when you need it, aggressive when you want it\u003c\/h3\u003e\n  \u003cp\u003e\n    The included remote puts you in control. Open the valves for maximum flow and a deeper, sportier character, close them for near OE levels of civility, or use AUTO so the system opens at a preset RPM. The supplied OBD plug-in controller makes operation intuitive and installation straightforward.\n  \u003c\/p\u003e\n  \n  \u003ch3\u003eBuilt with precision for smooth flow and reliability\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eSeven-axis CNC mandrel bending - up to 98 percent roundness for optimised gas speed\u003c\/li\u003e\n    \u003cli\u003eCrisscross and overlapping welding on high heat joints for durability\u003c\/li\u003e\n    \u003cli\u003eDirect spot welding with mechanical arms for strong, consistent welds\u003c\/li\u003e\n    \u003cli\u003eIntegrally moulded pipework with accuracy down to 0.025 mm\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003eOPF - GPF support\u003c\/h3\u003e\n  \u003cp\u003e\n    Running an OPF - GPF equipped car. A free-of-charge OPF delete solution is available on request, allowing fitment on OPF vehicles without fault codes - no ECU coding required. Ask us to include it when ordering.\n  \u003c\/p\u003e\n  \n  \u003ch3\u003eRecommended pairings\u003c\/h3\u003e\n  \u003cp\u003e\n    For an even more pronounced tone and additional flow, many owners add either the Stone BMW B48E F40 M135i xDrive Catless Downpipe or the Stone BMW B48E F40 M135i xDrive Eddy Catalytic Downpipe.\n  \u003c\/p\u003e\n  \n  \u003ch3\u003eCompatibility\u003c\/h3\u003e\n  \u003cp\u003e\u003cstrong\u003eEngine:\u003c\/strong\u003e BMW B48E\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eBMW 1 Series F40 M135i xDrive 2018+\u003c\/li\u003e\n    \u003cli\u003eBMW 2 Series F44 M235i xDrive 2018+\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003ePart numbers\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eAP548AS - F40 M135i xDrive\u003c\/li\u003e\n    \u003cli\u003eAP548BS - F44 M235i xDrive\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003eWhat you will love\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eSporty, characterful soundtrack with valves open - calm and comfortable with valves shut\u003c\/li\u003e\n    \u003cli\u003eReal-world performance uplift backed by Stone dyno development\u003c\/li\u003e\n    \u003cli\u003eDirect-fit installation thanks to accurate scanning and precision welding\u003c\/li\u003e\n    \u003cli\u003eReliable, plug-in OBD control for instant valve operation\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003ch3\u003eWarranty\u003c\/h3\u003e\n  \u003cp\u003e\n    Stone Exhaust 2 Year Warranty.\n  \u003c\/p\u003e\n  \n  \u003ch3\u003eProfessional fitting\u003c\/h3\u003e\n  \u003cp\u003e\n    Prefer expert installation. MJ Modifications offers professional fitting in Warwickshire. Request a tailored quote at \u003ca href=\"mailto:info@mjmodifications.co.uk\"\u003einfo@mjmodifications.co.uk\u003c\/a\u003e.\n  \u003c\/p\u003e\n  \n  \u003ch3\u003eVideos\u003c\/h3\u003e\n  \u003cp\u003e\u003cstrong\u003eStone Valvetronic System Installation\u003c\/strong\u003e\u003c\/p\u003e\n  \u003cdiv\u003e\n    \u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/V5c4VEyO1EM\" title=\"Stone Valvetronic System Installation\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen\u003e\u003c\/iframe\u003e\n  \u003c\/div\u003e\n  \u003cbr\u003e\n  \u003cp\u003e\u003cstrong\u003eBMW B48E F40 M135i xDrive - Stone Catless Downpipe plus Valvetronic catback sound\u003c\/strong\u003e\u003c\/p\u003e\n  \u003cdiv\u003e\n    \u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/jaAQnBLGOV8\" title=\"BMW B48E F40 M135i xDrive with Stone Catless DP plus Valvetronic Cat-back System Sound\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen\u003e\u003c\/iframe\u003e\n  \u003c\/div\u003e\n  \n  \u003ch3\u003eImage gallery\u003c\/h3\u003e\n  \u003cp\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1272\/9301\/files\/Stone_Exhaust_BMW_B48E_F40_M135i_xDrive_Cat-Back_Valvetronic_Exhaust_Stone_Exhaust_USA-1_600x600.png?v=1616993075\" alt=\"Stone Valvetronic catback for BMW F40 M135i xDrive - MJ Modifications UK\"\u003e\n  \u003c\/p\u003e\n  \u003cp\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1272\/9301\/files\/Stone_Exhaust_BMW_B48E_F40_M135i_xDrive_Cat-Back_Valvetronic_Exhaust_Stone_Exhaust_USA-2_600x600.png?v=1616993084\" alt=\"Stone switchable exhaust BMW M135i F40 - MJ Modifications UK\"\u003e\n  \u003c\/p\u003e\n  \u003cp\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1272\/9301\/files\/Stone_Exhaust_BMW_B48E_F40_M135i_xDrive_Cat-Back_Valvetronic_Exhaust_Stone_Exhaust_USA-3_600x600.png?v=1616993101\" alt=\"BMW B48E F40 M135i catback rear section by Stone - MJ Modifications UK\"\u003e\n  \u003c\/p\u003e\n  \u003cp\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1272\/9301\/files\/Stone_Exhaust_BMW_B48E_F40_M135i_xDrive_Cat-Back_Valvetronic_Exhaust_Stone_Exhaust_USA-4_600x600.png?v=1616993113\" alt=\"Stone valve-controlled system for BMW M135i xDrive - MJ Modifications UK\"\u003e\n  \u003c\/p\u003e\n  \u003cp\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1272\/9301\/files\/Stone_Exhaust_BMW_B48E_F40_M135i_xDrive_Cat-Back_Valvetronic_Exhaust_Stone_Exhaust_USA-5_600x600.png?v=1616993125\" alt=\"Stone rear section BMW F40 M135i xDrive - MJ Modifications UK\"\u003e\n  \u003c\/p\u003e\n  \u003cp\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1272\/9301\/files\/Stone_Exhaust_BMW_B48E_F40_M135i_xDrive_Cat-Back_Valvetronic_Exhaust_Stone_Exhaust_USA-6_600x600.png?v=1616993139\" alt=\"Close up Stone Valvetronic BMW F40 M135i - MJ Modifications UK\"\u003e\n  \u003c\/p\u003e\n  \n  \u003ch3\u003eHelpful search phrases\u003c\/h3\u003e\n  \u003cp\u003e\n    BMW 1 Series M135i F40 performance system, BMW 2 Series M235i F44 Gran Coupe sports exhaust, B48E sound upgrade, active valve exhaust BMW, switchable valve rear section, remote valve controller OBDII, plug-in OBD valve control, M135i xDrive catback UK, M235i xDrive catback UK, GPF back exhaust BMW, OPF solution BMW, BMW F40 M135i sports system, BMW F44 M235i switchable system, best sounding system for M135i, best sounding system for M235i, BMW B48 engine exhaust upgrade, valve controlled BMW 1 Series, valve controlled BMW 2 Series, performance rear section BMW, Stone Exhaust UK dealer, MJ Modifications BMW tuning.\n  \u003c\/p\u003e\n  \n\u003c\/div\u003e","brand":"Stone Exhaust","offers":[{"title":"F40 M135i xDrive \/ Flat Cut Gloss Carbon Fiber (102mm)","offer_id":56008692466050,"sku":null,"price":3256.03,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0871\/5445\/8937\/files\/Flat_Cut_Gloss_Carbon_Fibre_102mm_1946x_127d63fe-6f7c-4d1a-9aab-5b6688e32704.png?v=1764090840","url":"https:\/\/mjmodifications.co.uk\/products\/stone-exhaust-bmw-b48e-f40-m135i-xdrive-cat-back-valvetronic-exhaust-system","provider":"MJ Modifications","version":"1.0","type":"link"}