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Cat Back Exhaust [Mk3 Focus ST]

This part does not affect the base vehicle warranty.

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 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 Wagon models. See wagon specific product here.

    Customer Reviews
    4.8 Based on 75 Reviews
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    Filter Reviews:
      Darryl V.
      United Kingdom United Kingdom

      Cat back exhaust MK3 ST3

      I’ve just had it fitted today I have to say my local garage has done an amazing job and it looks brilliant. It definitely has a different but better note to it but not too loud or obnoxious. I can definitely feel the difference with the response and power. My car puts a smile on my face whenever I drive it this has just made it broader. Thankyou mountune. Another very happy customer. Look forward to more purchases from you in the future.

      United Kingdom United Kingdom

      Exhaust review

      Really like the look of the product. Can tell how well made it is and has improved the tone to the car nicely. Only reason it's not 5* is because of the delay to delivery.

      United Kingdom United Kingdom

      Ford Focus MK3 ST PFL.

      Very good sound, not too loud but a big improvement on the car ;D. Thank u.