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The best modifications for the MK4 Focus ST

The best modifications for the mk4 focus st

Performance Fords have been a part of British car culture for decades. The Focus ST and RS Models being affordable, engaging hot hatches that let drivers safely and reliably do daily driving duties whilst also having the performance to back it up.

The latest Mk4 Ford Focus ST released in 2018 is an evolution of, and the natural step up for the Fiesta ST owner that needs more space, wants more performance and is ready to upgrade. The Mk4 Focus ST uses a variant of the 2.3 Ecoboost from the MK3 RS model. As it stands, the ST is the hottest Focus you can buy as Ford have confirmed there won’t be an RS in this generation due to regulations and development costs.

The Mk4 Focus ST is a performance bargain for someone who wants to have fun on a spirited drive but can also fit the family in to go on a day out.

With a few choice mods, you can make your Mk4 ST something really special.

Mk4 Focus ST Remap

If you want the best bang-for-buck performance upgrade for your Mk4 ST then a revo remap will drastically change the driving performance and characteristics of your car.

A stage 1 remap will take your Focus from the 280ps and 310lbft of torque up to nearly 335ps and 384lbft.

The best modifications for the mk4 focus st

If you remap your ST then you’ll never go back, and chances are you’ll remap your next car too.


Mk4 Focus ST Air Intakes

The exciting thing about the 4th gen ST is that unlike many competitors who are reducing the engine size. the ST engine is actually upsized from the 2.0 in the previous generation so there is an upgrade in sound and performance. As mentioned above, it’s a variant of the 2.3 from the old Focus RS and Ecoboost Mustangs.

Whilst it’s a strong performer stock, you can get better performance, and intake sound from adding an aftermarket intake to your ST, you’ll also be able to get more out of your remap or further tuning with a good intake.

If you’re not looking to replace the entire intake, you could slot in a replacement filter panel to release some of that intake restriction the OEM one comes with.

Mk4 Focus ST Intercoolers

Ford owners are supremely passionate about cooling, its rare you’ll see a modified forced induction Ford without an aftermarket intercooler, at shows and events this is partly because the grill of most performance Fords allows you to see the intercooler between the slats.

Most owners go for Airtec intercoolers because they get to show off the large Airtec logo through the grille, but there are a wide variety of intercoolers available if you’re looking for something more subtle.

If you’re looking to go past stage 1 with your MK4 focus ST then an intercooler is a must-have to ensure your vehicle

Springs & Suspension

The suspension set up from Ford is developed to have the car sit well in the corners without giving everyone else in the car a tough time, however, it’s lacking if you’re looking for a more planted experience on the back roads. Plus, springs will improve the stance of your ST, which will be subtle, but they look so much better dropped.

Whilst a remap will give you the best additional performance per £, springs are exceptionally affordable and you’ll instantly feel a difference when you first take the car out after it’s been done.


Like most exhausts these days, its probably the most disappointing part the car, while it sounds better than the standard Focus, it’s nowhere near as exciting as it should be. By installing an aftermarket exhaust, not only will you smile every time you start the car up but you’ll also eek out a little extra performance from having a free-er flowing exhaust installed on the vehicle – plus many aftermarket exhausts tend to weigh less than their OEM counterparts too.

If you’re not looking to invest in a full system but would like to improve the sound of your car then an excellent entry point to modifications is a decat downpipe.

Maxton Design Body Kit Styling

Some people appreciate the subtle styling of the ST and enjoy it blending in at the local car park, however, like many petrolheads we prefer to make vehicles our own. Adding specific body kit parts can really make it unique to you.

Most people go for the splitter first but if you’ve got a performance car with a decent exhaust on it, framing it with an aftermarket diffuser can really take the rear of the vehicle up a notch.

If you really want to push your ST to the aesthetic limits then think about installing bonnet vents!

Rieger Ford Focus Mk4 ST Kits

Here at Progressive Parts we love the Mk4 Focus ST, it’s the best Focus you can buy at the minute and can be an absolute workhorse in one moment and a really engaging drive the next and you’ll love it even more with some of the choice mods we’ve recommended above.

One thought on “The best modifications for the MK4 Focus ST

  1. Sebastian Meberg says:

    This might be a dumb question. But can I fit mk4 ST parts on my mk4 1.5l Ford Focus?
    Or even parts from mk3? Will it fit?
    I’m looking to get my exhaust changed and maby get an induction kit, but its so hard to find performance parts for Focus mk4 in norway..

    Looking forward to hear from you!

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