Modified Ford Focus ST for Sale in the UK
The Mk3 Ford Focus ST is one of the most popular platforms for hot hatch modification in the UK. Powered by Ford's 2.0-litre EcoBoost turbocharged petrol engine producing 250bhp in standard form, the Focus ST offers a strong, well-supported tuning platform with a wide range of both factory-endorsed and aftermarket upgrade options available.
Modified Focus ST models for sale commonly range from Mountune-upgraded examples with factory warranty preservation to full stage 2 and stage 3 builds with hybrid or big turbo conversions producing 350–400bhp. The Focus ST's front-wheel drive layout responds well to LSD upgrades and suspension tuning, making it a capable handling car alongside its impressive straight-line performance.
Mountune's MP275 and MP305 upgrade packages are uniquely popular on the Focus ST as they're officially endorsed by Ford and don't void the manufacturer's warranty — making them an attractive option for buyers who want reliable, documented performance gains. Beyond Mountune, the aftermarket for the 2.0 EcoBoost is extensive, with multiple ECU tuning options, intercooler upgrades, downpipe options and induction kits available.
Browse live modified Ford Focus ST listings on Madlows, the UK's dedicated modified car marketplace. Each listing includes full modification details, seller contact information, and pricing. Whether you're after a tastefully upgraded daily driver or a high-power weekend build, find your next Focus ST here.
Modified Ford Focus ST Listings
0 cars available
Be the first to list your modified Ford Focus ST on Madlows.
List your Focus ST todayPopular Ford Focus ST Modifications
The 2.0 EcoBoost engine and Focus ST's agile chassis support a wide range of upgrade paths, from factory-endorsed Mountune packages to full custom builds.
Engine Tuning
- • Mountune MP275 & MP305 packages
- • Stage 1 ECU remaps (290–310bhp)
- • Stage 2 intercooler & downpipe builds
- • Hybrid turbo conversions (350–400bhp)
- • Upgraded induction kits
- • Performance exhaust systems
Handling & Brakes
- • Quaife ATB limited slip differential
- • BC Racing or KW coilovers
- • Uprated suspension bushes
- • Brake upgrade kits
- • Aftermarket alloy wheels
- • Lower profile tyres
Ford Focus ST Buyer's Guide
LSPI Prevention & Fuel Quality
Low-Speed Pre-Ignition (LSPI) is a risk on direct injection turbocharged engines like the 2.0 EcoBoost when operated on low-octane fuel or with certain engine oil formulations. Always use 98-RON or higher fuel on a tuned Focus ST. Verify that the tune has been calibrated for UK premium fuel grades and that the correct engine oil specification has been used.
Intercooler Efficiency
The standard Focus ST intercooler is adequate for mild builds but becomes a limiting factor on higher-power applications. On hot days, power loss through heat soak is a known characteristic of the stock intercooler. Verify that higher-stage builds have an upgraded front-mount or top-mount intercooler installed.
Mountune Verification
If the car claims to have a Mountune upgrade, verify this with Mountune using the vehicle's VIN. Mountune keeps records of vehicles they have upgraded, and genuine Mountune hardware will be identifiable. Cloned or imitation Mountune parts have appeared on the market and should be treated with caution.
Explore More Modified Cars on Madlows
Frequently Asked Questions — Modified Ford Focus ST
How much power can a tuned Ford Focus ST make?
A stage 1 ECU remap on the Mk3 Focus ST's 2.0-litre EcoBoost engine typically raises output from the standard 250bhp to around 290–310bhp with improved torque delivery. Stage 2 builds with an upgraded intercooler and downpipe push into the 330–360bhp range. Mountune upgrades — factory-endorsed and warranty-friendly — offer a reliable path to around 275bhp (MP275) or 305bhp (MP305). Hybrid turbo conversions can reach 400bhp+ with full supporting modifications.
What are Mountune upgrades and are they worth it?
Mountune is Ford's official performance upgrade partner, offering hardware and software upgrades that retain the Ford warranty on applicable vehicles. The Mountune MP275 kit (275bhp) and MP305 kit (305bhp) are popular choices for Mk3 Focus ST owners who want reliable performance gains without voiding their manufacturer's warranty. Mountune upgrades use high-quality components and purpose-written tunes, and come with good resale appeal.
Is the 2.0 EcoBoost engine in the Focus ST reliable when tuned?
The Ford 2.0 EcoBoost (Mk3 Focus ST, engine code GTDI) is generally a reliable unit when properly maintained. Key areas to monitor include the inlet manifold (carbon build-up on direct injection engines), the intercooler efficiency on hot days, and the coolant system. On higher-power builds, LSPI (Low-Speed Pre-Ignition) can occur if the engine is operated on low-quality fuel. Use 98-RON fuel and ensure the tune accounts for UK fuel quality.