Another great Fiesta mod? You got it. There’s no denying that the Mk6 ST has become a legend in its own lifetime, and what with the fact that you can pick one up for the price of a Dairylea Dunker nowadays, they’re only set to continue smashing the UK scene, both on the road and even more on the track.

The thing is though, these little 2-litre stormers may be suitably fast and agile, but any true weekend warrior will tell you that nothing will transform your Fiesta, or any other car for that matter, like a proper limited slip diff.

The truth is that an LSD is the only chassis tweak designed to bias torque – essentially limiting wheel slip – to aid traction. They’re also something of an essential for a hard-driven FWD motor, especially one running significantly more power than standard.

Anyway, the good news is that the guys at Rally Designs can now sort you out with this amazingly well-priced Blackline diff to perform all this torque-based witchcraft. A bona fide racecar mod and no mistake.

Price £594

For more info see Rally Design