What's it like?
It doesn't feel drastically different in normal use. Tool about in a moderately enthusiastic manner and the Mountune Focus RS delivers much the sort of robust, distance-warping performance that the standard RS already rolls out in abundance. It's when you find the right situation to roll your sleeves up, say a prayer, select Race and really go for it that the Mountune bits pay off.
The throttle response feels a touch crisper and the engine even more rabid from around 3000rpm onwards. You're not going to get booted into a hedge by some unexpected turbo lag, either. Even with a bit more power, the 2.3-litre turbo'd four-pot is joyously unfettered by ungainly peaks or plateaus in its power delivery, building speed progressively but with furious intent right through to the red line.
It sounds a touch different; a bit more of a satisfying hiss of released pressure as you lift off the throttle, but otherwise much the same purposeful, resonant burble punctuated with the obligatory overrun pops and crackles. Mountune does, of course, offer a wide variety of other upgrades, including a £1050 'axle-back exhaust' (which also doesn't affect the warranty), but our car didn't have it fitted.
The suspension is unaltered, so in hard use, you still get the addictive progression from a dependable whiff of understeer, through bullish neutrality before edging into manageable oversteer. Equally, the ride remains a bit wearisome in terms of its stiff vertical movement, but few will quibble, given the handling intensity you're getting in return.
Should I buy one?
Hell, yes. The Focus RS is all about those moments when it feels far more than a hot hatch ever should; more mobile, more aggressive, more like a Nissan GT-R with five doors and a bargain price tag. The Mountune kit only makes those moments a fraction more spectacular, but it's a noticeable, euphoric fraction.
Plus, this upgrade nudges the RS even closer to titan hatches, such as the Mercedes-AMG A 45 and Audi RS3, and for not much cash in this context. So yes. Do buy a Focus RS, and do buy this Mountune kit. You won't ever regret either decision.
Ford Focus RS Mountune FPM375
Location Surrey, UK; On sale now; Price £32,149; Engine 2261cc, turbo, petrol; Power 370bhp at 6000rpm (in overboost); Torque 376lb ft at 2000rpm; Gearbox 6-spd manual; Kerb weight 1547kg; 0-62mph 4.5sec; Top speed 165mph; Economy 36.7mpg; CO2/tax band 175g/km, 37% Rivals Mercedes-AMG A 45, Volkswagen Golf R