Choosing a Milltek exhaust for your Focus ST generation
The Mk2 ST 225 has a cat-back, a sports cat downpipe and a de-cat downpipe, with a locking bolt kit available as a spare part. The Mk3 ST 2.0 EcoBoost is split by body style, so pick the right one: the five-door hatch and the estate each have their own cat-back, sports cat downpipe, HJS Tuning ECE downpipe and de-cat downpipe. The Mk3 ST 2.0 TDCi diesel hatch has its own cat-back.
The Mk4 ST 2.3 EcoBoost (2019 on) has a petrol particulate filter, so instead of a cat-back it takes a filter-back system, which replaces everything behind the factory filter and leaves the filter in place. Hatch and estate are again listed separately, each with a filter-back, sports cat downpipe, de-cat downpipe and GPF/OPF bypass.
Focus ST downpipes: sports cat, HJS ECE or de-cat?
Every petrol Focus ST generation has a choice of downpipe. The sports cat downpipes and the Mk3 HJS Tuning ECE downpipes keep a catalyst in the system. De-cat downpipes are for off-road and competition use only and will fail an MOT emissions test, and the Mk4 GPF/OPF bypass is a louder, motorsport-oriented part. Expect to need an ECU remap with most downpipes, and check the fitment option, as some are listed to suit the OE system or a Milltek cat-back. Browse every downpipe and sports cat we list.
Sound levels and tips for the Focus ST
Systems come in resonated, part resonated and non-resonated forms, with race versions on some listings. Resonated is the one for long motorway runs, with less drone; non-resonated and race versions are louder. Tip choices include GT-100 and GT-115 designs in polished, titanium, burnt titanium and Cerakote Black, plus JET carbon fibre and polished trims, all shown on our tip styles page. Weighing up the four-wheel-drive car? See the Focus RS range.
Buying Focus ST parts from Milltek Exhaust Shop
Enter your reg at the top of this page to see only the parts listed for your Focus ST. UK delivery is free, overseas orders ship worldwide, Klarna and PayPal are accepted, and our Stoke-on-Trent workshop can fit the system for you.