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Cat Back Exhaust [Mk3 Focus ST Wagon/Estate]

mountune has many years of experience in engineering exhaust systems with the objective of increased power and response, coupled with an enhanced exhaust tone and appearance.

The mountune Performance mk3 Focus ST wagon/estate Cat Back Exhaust system is manufactured from 2.5” diameter, AISI 304 stainless steel (EN58E) mandrel-bent tubing with lazer cut flanges. All muffler assemblies are robotically TIG welded AISI 304 stainless steel for long life under extreme performance and feature consistent internal diameter throughout the entire length of the assembly.

To ensure improved performance while controlling sound, each muffler includes a three-layer hybrid synthetic sound absorption packing that eliminates droning, booming, and other undesirable tones. Tubing diameter also has a major impact on sound quality and careful consideration was given to size and performance.

Also incorporated are slip-fit connections at various strategic points to allow for easy installation and adjustment.

Crucially, the mountune cat back exhaust is the only exhaust system that will not affect your base vehicle warranty and in addition, comes with a mountune limited lifetime warranty*.


  • Manufactured from AISI 304 2.5” mandrel bent stainless steel tubing
  • TIG welded construction AISI 304 stainless steel hangers
  • Mufflers feature consistent internal diameter 3-layer hybrid synthetic muffler packing effective to 900 degrees C
  • Large 4” rolled edge, polished stainless steel tips with mountune logo
  • Full width rear hanger ensures stable tip location
  • Heavy duty "boss" type clamps
  • CAD engineered and designed
  • Limited lifetime warranty*
  • Does not affect Ford vehicle warranty

Recommended to fit in conjunction with mk3 Focus ST Sports Cat / Downpipe.

Please note: Not compatible with Hatch models. See hatch specific product here.

*Please contact us for warranty terms and conditions.

    Customer Reviews
    4.9 Based on 7 Reviews
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      United Kingdom United Kingdom

      Just awesome

      The quality of this exhaust is top notch, no flaws, perfect welds, excellent finish on the tips with the logo as well. So I came from a resonator delete on a stock exhaust, it was on there when I bought the car so cannot compare to a full stock exhaust. I am still running the stock cat/downpipe for now. Initial drive after putting the exhaust on I could immediately hear a difference, a much deeper note/tone compared to before, could definitely hear the difference but it wasn't excessively loud or as loud as I thought it was going to be, at this point I'd only driven it around the shops and town nothing aggressive it is maybe a little more noticeable than stock around town/traffic but it's not gonna wake your neighbours when you come home late at night. And then my jaw hit the floor 2 days later when I took it out for a spin and floored it up to 70mph in second gear onto a motorway, the sound was absolutely incredible, very difficult to describe the sound, initially starts off as a deep growl and then as you hit 4000rpm it's really starts to scream, and you can hear the like wooshing of gasses going through the exhaust it's just makes the car sound so powerful. I am beyond pleased with the exhaust and it makes me smile every time I put my foot down now. Also there is no noticeable droning when sat at 70mph on the motorway, I feel maybe the stock exhaust with the resonator delete had a lot more drone than this. Also didn't just get this exhaust for sound, looking at making my way to the mr300 tune over the next year, really looking forward to seeing how this car will evolve over time with me.

      United Kingdom United Kingdom

      Cat Back Exhaust

      Very fast dispatch from the Mountune team. Very well packaged, excellent craftmanship can't wait to fit it with the Sports Cat and see/feel the difference.

      Netherlands Netherlands

      Premium quality catback exhaust

      i love the design of this catback! most beautifull weldings I have ever seen. the end tips are better than earlier reviews, these tips are a new type i geuss. with a new mountune logo. sound is verry nice, sometimes a bit too load in the cabin but only whith the pedal to the metal. slightly disapointed that the diameter of the catback smaller is than the one of the downpipe. i believe that the flow at that point is ristricted. but performance wise its a lot better than stock. a specialy the sound!! love it!

      mountune Cat Back Exhaust [Mk3 Focus ST Wagon/Estate] Reviewmountune Cat Back Exhaust [Mk3 Focus ST Wagon/Estate] Reviewmountune Cat Back Exhaust [Mk3 Focus ST Wagon/Estate] Review


      Thanks for the positive feedback and glad you're enjoying your new exhaust system. Due to the setup of the resonators, the bore size did not need to be any bigger and we've tested this setup to much higher power outputs than any of our current power upgrades, so you don't need a larger bore system, unless you like lots of drone!