{"product_id":"isr-performance-series-ii-mbse-resonated-catback-bmw-e46-early-323-328","title":"ISR Performance Series II - MBSE Resonated Catback - BMW E46 Early 323\/328","description":"\u003cp\u003eThe ISR Performance Series II MBSE Resonated Catback is the complete modular exhaust system for the BMW E46 Early 323\/328. Stainless steel construction, dual 2.5 inch mid pipes flowing into a resonator and 3 inch transition, finishing with a dual 2.5 inch tip muffler section and extended tips designed to clear deeper aero bumpers.\u003c\/p\u003e\n\n\u003ch3\u003eWhat It Does\u003c\/h3\u003e\n\u003cp\u003eThe factory E46 exhaust is restrictive and tuned for quiet operation. The ISR Series II MBSE replaces it with a free-flowing path that improves exhaust scavenging, drops weight, and unlocks the inline-six tone the E46 platform is supposed to have. The MBSE rear muffler section keeps the tone aggressive under throttle while staying noticeably more refined and daily-friendly than the straight-pipe EP Dual configuration.\u003c\/p\u003e\n\n\u003cp\u003eSeries II construction also routes the pipes for increased ground clearance compared to traditional catback layouts, which matters on lowered E46s scraping over driveways and speed bumps. The extended tips are designed to fit deeper aftermarket aero bumpers and still provide an aggressive look on stock bumpers.\u003c\/p\u003e\n\n\u003ch3\u003eCritical Fitment\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eEarly 323\/328 ONLY.\u003c\/strong\u003e This catback is designed around the 323\/328 header flange orientation and placement. It will NOT fit late 325\/330 vehicles. If you have a 325 or 330, the Late 325\/330 MBSE variant covers that fitment.\u003c\/p\u003e\n\n\u003ch3\u003eHeader Requirement\u003c\/h3\u003e\n\u003cp\u003eMust use the OEM 323\/328 header OR an aftermarket header with the same flange orientation and placement.\u003c\/p\u003e\n\n\u003ch3\u003eOther Compatibility Notes\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eNOT tested on automatic transmission vehicles - development was done on manual cars\u003c\/li\u003e\n\u003cli\u003eNOT tested on non-USDM chassis\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eModular Architecture\u003c\/h3\u003e\n\u003cp\u003eThis catback uses ISR's Series II modular construction. Once installed, you can swap the rear section to EP Dual for a louder straight-pipe configuration (sold separately) without buying a new exhaust.\u003c\/p\u003e\n\n\u003ch3\u003eEP Dual vs MBSE\u003c\/h3\u003e\n\u003cp\u003eBoth Series II E46 catbacks share the same resonated mid section. The difference is the rear: the MBSE uses a muffler section for a more refined, daily-friendly tone with less drone. The EP Dual uses a straight-pipe rear for maximum volume and a race-inspired sound. Either can be swapped to the other configuration later via the modular architecture.\u003c\/p\u003e\n\n\u003ch3\u003eFitment\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eBMW E46 323\/328 (Early) USDM, manual transmission recommended\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat's in the Box\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e2x Flex mid pipes\u003c\/li\u003e\n\u003cli\u003e1x MBSE rear section\u003c\/li\u003e\n\u003cli\u003e1x Resonated mid section\u003c\/li\u003e\n\u003cli\u003e1x Gasket and hardware pack\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eProduct Details\u003c\/h3\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eBrand:\u003c\/strong\u003e ISR Performance\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003ePart Number:\u003c\/strong\u003e IS-S2MBSER-E46-E\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eType:\u003c\/strong\u003e Series II MBSE Resonated Modular Catback Exhaust\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eVehicle Fitment:\u003c\/strong\u003e BMW E46 Early 323\/328 (USDM)\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eHeader Requirement:\u003c\/strong\u003e OEM 323\/328 header or aftermarket with same flange orientation - NOT compatible with 325\/330\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eMaterial:\u003c\/strong\u003e High-quality stainless steel\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eMid Pipe Diameter:\u003c\/strong\u003e Dual 2.5 inch\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eCenter Section:\u003c\/strong\u003e 3 inch\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eRear Configuration:\u003c\/strong\u003e Dual 2.5 inch tip muffler section, extended tips\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eTone Profile:\u003c\/strong\u003e Resonated with muffler rear - aggressive but daily-friendly, reduced drone\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eArchitecture:\u003c\/strong\u003e Series II modular (rear section interchanges with EP Dual)\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eTransmission Note:\u003c\/strong\u003e Not tested on automatic transmissions\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eChassis Note:\u003c\/strong\u003e Not tested on non-USDM chassis\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eSold:\u003c\/strong\u003e Complete catback (mid + rear)\u003c\/p\u003e\n\u003cp style=\"margin-bottom: 4px;\"\u003e\u003cstrong\u003eLegality:\u003c\/strong\u003e Off-road and competition use only\u003c\/p\u003e","brand":"ISR Performance","offers":[{"title":"Default Title","offer_id":45957128945861,"sku":"IS-S2MBSER-E46-E","price":907.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0767\/2718\/9701\/files\/E46mbse__76799.1716469798.1280.1280__53746.1716909676.500.659.jpg?v=1773346824","url":"https:\/\/www.isrcompetition.com\/products\/isr-performance-series-ii-mbse-resonated-catback-bmw-e46-early-323-328","provider":"ISR Competition","version":"1.0","type":"link"}