Mk3 Focus ST Cat Back Exhaust - Fully Fitted at mountune HQ


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 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 performance 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

Please note: the price shown for this product includes installation at mountune HQ in Hutton, Essex and is not transferrable to any other Ford dealer or installer. 

Please specify your preferred installation date in the 'notes' section when checking-out; our workshop team will then contact you back to confirm this date. If we can't accommodate your preferred choice, the team will discuss with you other available dates, that are still acceptable to you.

Customer Reviews

5 Based on 8 Reviews
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Dan K


Love the tone of this exhaust and it doesn't drone on the motorway. Spent a while researching and wondering if it was the right thing to do but as soon as I started it and left the industrial estate I knew I'd made the right choice. All staff friendly and helpful. Will definitely be using Mountune again. Thank you!

Stephen Webb

Cat back exhaust - 2017 Focus ST3

Great service from beginning to end. Exhaust looks and sounds brilliant. Waiting area fantastic. Thanks Ryan.

Martin P.
United Kingdom

Its just getting better

Service by Mountune Hutton uk was from beginning to end first class. I now have my ST sounding just as it should do . Looks brilliant sound just awsome. Now what shall i have next ?? MRP

Martin P. verified customer review of Mk3 Focus ST Cat Back Exhaust - Fully Fitted at mountune HQMartin P. verified customer review of Mk3 Focus ST Cat Back Exhaust - Fully Fitted at mountune HQ

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