The Kia Stinger GT S came out of nowhere. While the rest of Kia’s range consists of eminently sensible hatchbacks and SUVs, the Stinger GT S is a bit mad – a large and luxurious rear-wheel-drive hatchback with swoopy couple-like styling and a socking-great turbo V6 under the bonnet. And a chassis set-up that makes it so easy to drift, your gran could do so wearing flippers. In short, it’s a genuine rival to the likes of the BMW 340i and Mercedes-AMG C43.

What the Stinger GT S definitely isn’t, though, is a track car. It’s a hefty thing at 1855kg and it only takes a couple of big stops for the brakes to start wilting under the pressure. Enter the Stinger GT420, a one-off track car created as an out-of-hours project by Kia UK’s press fleet garage and Kia’s European engineering centre in Germany.

The project actually started as a way of rescuing the first pre-production Stinger GT S to arrive in the UK. Since it had been subjected to a litany of homologation tests, completed an arduous dealership tour and appeared on both Top Gear and The Grand Tour, it seemed a shame to just chuck it in a crusher – it’s planned fate.

Safe from the jaws of death, the team set about beefing up the GT S for the track.

Under the bonnet, HKS spark plugs, a K&N air filter and catalyst-free Milltek exhaust were added to liberate 422bhp and and 413lb/ft of torque – up from 365bhp and 376lb/ft. A bigger transmission cooler was added and the sporty gearbox modes recalibrated to take advantage of the power boost.

Underneath, there’s a set of lightweight 18in OZ Racing Leggera wheels wrapped in Pirelli Trofeo R tyres. Standard, non-adapative Stinger dampers are used, teamed with Eibach Pro lowering springs. Bigger anti-roll bars have been added, the suspension geometry tweaked to suit and the electronics massaged to work better on track. And yes, the brakes have been addressed, the limp standard set-up swapped for huge high-performance discs – 380mm at the front – and six-pot Brembo calipers.

All this counts for nothing if the GT420 is still a bit lardy, so the interior was completely gutted, slashing 150kg off the kerbweight. All the usual safety gear including a substantial rollcage was added back in.

Journalists got a chance to drive the GT420 at Silverstone earlier this week and, by all accounts, it’s a proper track car that’s really fun to drive.

Kia insists that the Stinger GT420 is just a bit of fun, but does concede that serious effort went into its creation and development. Does that suggest a more hardcore version of the Stinger is in the works? Time will tell, but we certainly hope so.

Click here for more information

By Graham King