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6 reviews


Cat Back Exhaust [Mk3 Focus ST Wagon/Estate]

This part does not affect the base vehicle warranty.

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
    4.8 Based on 6 Reviews
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    Filter Reviews:
      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!

      Matthew W.
      Norway Norway
      Ford focus st estate exhaust

      First I have to say ,, it was very easy for installation, took me lest that half hour to install but too me 2 hours to get the old one out , due to rust . The is not what I was expecting but it get better and better after a while. Secondly, mountune need to start have documentation for the exhaust (certificate of authentication)., people in other countries need it to get there car acceptable for road control (Norway).


      Thanks for your feedback. Unfortunately, it's not as easy as simply providing documentation. There is normally additional timescales, testing and significant costs involved to get an EC-level approval which is not something that is always possible for various reasons. We continue to explore homologation opportunities.