Search our store


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 will 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 6 Reviews
    5 ★
    4 ★
    3 ★
    2 ★
    1 ★
    Customer Photos
    Write a Review Ask a Question

    Thank you for submitting a review!

    Your input is very much appreciated. Share it with your friends so they can enjoy it too!

    Filter Reviews:
      Taiwan Taiwan


      Perfect product quality, fast shipping, pretty complete packaging. This product makes the car perform better

      mountune Downpipe / Sports Cat [Mk4 Focus ST] Review
      United Kingdom United Kingdom

      Great product

      Great, had to wait a little for Stock, but Mountune online team were always happy to help, Downpipe was a little tricky to fit, but no major problems, couple this with the sports GPF, exhaust and M365 map, this product really brings the car to life, absolutely love it, 3rd and 4th gear pull is epic and addictive !

      Alex B.
      United Kingdom United Kingdom

      Another amazing part from Mountune

      I collected this in person along with the GPF-back and GPF. It's a lovely piece of hardware and crafted to perfection. It sounds amazing. The car revs louder and the pops and bangs are deeper and louder in sport mode, yet still at an appropriate level when driving normally. I fitted this along with the GPF, though I wouldn't recommend it unless you have the patience, the tools, and a helping hand. It took around 4 hours for the install with the car on axle stands, bearing in mind I'm a complete novice at this kind of thing. The whole air box, battery, and battery compartment had to come out along with the battery compartment bracket. I needed multiple socket extensions (10", 6", and 3") as well as universal joints. I was able to get an impact driver into where the battery bracket was to blast the turbo bolts in order to shift them enough to break them free with a big ratchet. All 3 turbo bolts can be accessed from the top of the engine by slipping the socket extensions around the pipes and hoses, but the downpipe bracket bolt had to be accessed from underneath after taking off the engine tray and very bottom small heatshield. The top lambda had to come off in order to twist the downpipe out and under the main heatshield. I used a dedicated 22mm lambda socket and blasted it with the impact driver since it was really stuck on there, making sure not to twist the cable too much as to not damage it. The bottom sensor was kept in place but just unplugged, and removed after I removed the downpipe. There's also a rubber hose attached to the downpipe that was very stuck on there. I simply gripped the end over the metal with some pliers and twisted until it broke free. Also, I removed the downpipe along with the big hanger then removed it from the downpipe after it was out. Putting in the Mountune one was just the exact opposite to removing the stock one, only easier since it wasn't as bulky with heat shielding. All in all the process wasn't too bad and definitely worthwhile. I regret absolutely nothing and am very pleased with it. If you are fit and healthy and have the tools then by all means fit it yourself, but it's a pretty hard job and you should probably get it fitted at a garage or Mountune themselves.



      That’s a serious job to attempt as a novice, so congrats on getting it done and glad you’re enjoying the hardware upgrades!