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3 reviews


Downpipe / Sports Cat [Mk4 Focus ST]


The mountune Downpipe / Sports Cat has been engineered for the Mk4 Focus ST to reduce exhaust back-pressure at the turbocharger, allowing faster response and additional power.

Featuring a large diameter motorsport-style, 200-cell count metal substrate honeycomb catalyst, to ensure effective, ultra high-flow performance, the mountune  downpipe sports cat is also constructed of 3” AISI 304 stainless steel mandrel-bent tubing with TIG-welded joins throughout for performance, reliability and aesthetics.

Additionally, robust OE-style mounting brackets and hangers are utilised to maintain perfect alignment and OE-like fitment and also incorporates an 8” stainless steel flexi section to help absorb shock and prevent OE hanger failure.

Revised engine calibration will be required for optimal performance and may emit the EML without it, but by simply replacing your downpipe and removing the inherent restriction, you can expect a peak performance gain of 10PS and 10Nm, with an even more substantial torque increase spread across the entire rev-range. 


  • 10PS / 15Nm peak power / torque increase
  • Large diameter motorsport-style, high-flow 200 cell catalyst
  • 3” AISI 304 mandrel bent stainless steel tube
  • Robust OE-type mounting bracket and hangers
  • 8” stainless steel flex joint
  • Compatible with all exhaust systems that retain the factory break point
  • Supplied with required gasket and hardware
  • TIG welded construction

This product has been designed and is intended for UK markets and complies with UK MOT tailpipe emissions regulations. Installation of this part on a vehicle that is driven on public roads outside the UK may violate other territories laws and regulations relating to emission requirements and motor vehicle safety standards.

    Customer Reviews
    5.0 Based on 3 Reviews
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    Filter Reviews:
      Stuart W.
      United Kingdom United Kingdom
      Good product but a few fitting problems

      Purchased this along with the GPF and the M365 upgrade (From M330) and will review the M365 after a few more miles. The downpipe is a lovely item, very well built, fits very nicely and sounds great. The only problem I had was fitting it, we could not get the nuts undone on the turbo end and after much swearing stripped the threads. This then meant ordering a new set of studs at a cost of around 17 quid but a lot of extra work to replace and refit. This is not Mountunes fault so I will not drop a star, but be aware because my local Ford dealer said this was not uncommon. If a set of studs were included in the kit it would have saved me a lot of time as the car ended up off the road for two days while I waited for the parts. All done now though and very pleased, hopefully never to be removed! No regrets.

      Colin M.
      United Kingdom United Kingdom
      Another quality item

      I had this fitted along with the sports gpf to complete the full turbo-back mountune exhaust system. Not the easiest part to fit though due to the bottom of the three nuts at the turbo being quite hard to reach, but got there in the end. After fitting it immediately felt like the turbo could spin up more quickly. The full exhaust system combined with the m365 calibration makes for a very quick car. Torque all through the rev range and no need to change down a gear for motorway overtakes. All in all another excellent part from mountune who just keep making the Mk4 ST better.

      mountune Downpipe / Sports Cat [Mk4 Focus ST] Reviewmountune Downpipe / Sports Cat [Mk4 Focus ST] Review
      Matthew R.
      United Kingdom United Kingdom
      Awesome Bit of kit

      Great looking and fits perfectly also feels like it’s freed up the engine a lot pulls hard on acceleration now.

      mountune Downpipe / Sports Cat [Mk4 Focus ST] Review