BMW F20 F21 M135i stainless catback system for 3 door and 5 door
Unlock a deeper soundtrack and sharper throttle feel from your 3.0 litre turbo six with this Cobra Sport rear system upgrade. Built from premium T304 stainless in 76.2 mm 3 inch tubing, it replaces the centre section and back box for a serious step up in tone, flow and style. Available in resonated or non resonated configurations to suit your taste, it is a direct performance enhancement for the 1 Series M135i hatchback.
Why choose this exhaust upgrade
Proven power increase on the non resonated catback, independent testing showed up to +10 bhp and +16 lb ft
Approximate 20 percent weight saving vs OE, system mass around 16.32 kg compared to 20.38 kg stock
3 inch 76.2 mm T304 stainless pipework for improved gas flow and durability
Beautiful twin 3.5 inch 88.9 mm tailpipes, choose inward rolled baffled tips or inverted highly polished tips
Choose your soundtrack, refined resonated option or a louder, more engaging non resonated setup
Supplied with all required fittings and gaskets for installation
Covered by the manufacturer guarantee for peace of mind
Choose your sound level
Resonated, includes centre silencer for a subtle performance tone that is civil on the motorway yet purposeful on throttle
Non resonated, removes the centre silencer for a more aggressive note and increased volume
Performance focused design
The larger bore 3 inch T304 construction helps the engine breathe, improving response and mid range pull. On the non resonated rear system, dyno testing delivered gains of +10 bhp with an additional 16 lb ft of torque. The lightweight construction trims roughly one fifth from the factory mass, enhancing the balance of the M135i.
Tailpipe finishes
Dual 3.5 inch inward rolled baffled tips
Dual 3.5 inch inverted highly polished tips
Compatibility
Designed for BMW M135i F20 5 door and F21 3 door models. Catback layout replaces the centre and rear sections from the catalyst back. Can be paired with a sports catalyst or de cat front section for a more extreme setup if desired.
What you get
Catback exhaust system in 76.2 mm T304 stainless steel, centre section and rear section
Your chosen tailpipe finish
Fitting hardware and gaskets
Fitting service
Want it fitted professionally. Book installation with MJ Modifications in Warwickshire. Email info@mjmodifications.co.uk for a quote. We run this system on customer cars and feedback has been excellent for sound quality, fit and finish.
Sound clips
Example, BMW M135i catback, resonated
Example, BMW M135i catback, resonated
Example, BMW M135i catback, non resonated
Example, BMW M135i catback, non resonated
Search friendly terms
BMW M135i F20 exhaust system, F21 M135i catback, BMW 1 Series M135i rear exhaust, stainless performance system, 3 inch M135i exhaust upgrade, resonated and non resonated BMW 1 Series M135i, twin 3.5 inch tips, Cobra Sport M135i catback.
