We adore the Focus RS, as it’s quite brilliant if not quite perfect. The five-star Ford pretty much redefines the hot hatch genre, which is why we rate it so highly – flaws and all.

In this latest collaboration, the celebrated tuning brand has worked with the blue oval to produce the Ford Performance by Mountune – or FPM375 – upgrade. That means the model is still covered by an official Ford warranty despite its additional 25bhp and 30lb ft of torque, and all for a miserly extra £899 over the RS’s standard purchase price. That buys you a re-flashed ECU, high-performance air filter, bespoke crossover duct and upgraded air re-circulation valve (or dump valve in popular parlance).

During day-to-day driving, the Focus RS is little more than its usual brilliant self. But when the time’s right to select ‘Race’ and put your foot down, Mountune’s intervention really comes into its own. Super-crisp throttle response accompanies an even more rabid engine feel from 3000rpm, and there’s no unexpected turbo lag, either, the 2.3-litre instead delivering its 370bhp smoothly, progressively yet furiously. The system enhances the standard RS’s purposeful, resonant burble and obligatory pops and crackles on the overrun. You can also spec a Mountune £1050 ‘axle-back exhaust’.

Unaltered suspension means hard driving sees the RS’s signature addictive progression from dependable understeer through bullish neutrality to manageable oversteer. The payoff for such handling intensity is a stiff ride, but who’s complaining?

The Mountune kit boosts the Focus RS’s spectacular performance by a noticeable, euphoric fraction. It’s relatively bargain priced against titan hatches such as the Mercedes-AMG A 45 and Audi RS3, too, which means that for hot hatch fans, buying this car should be a no-brainer.

Ford Focus RS Mountune FPM375

Price £32,149

Engine 2261cc, turbo, petrol

Power 370bhp at 6000rpm (in overboost)

Torque 376lb ft at 2000rpm

Gearbox 6-spd manual

Kerbweight 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