Sometimes, Kia takes its ‘Power to Surprise’ tagline a tad too seriously. Not that it’s a bad thing, because once in a while, you get a one-off car like this. Meet the Kia Stinger GT420, a special track monster that was developed between Kia’s UK and European engineering divisions. Leading the development team was Tyrone Johnson, a former Ford engineer who worked on performance hatches.

With that many hands on deck, the Stinger is in for quite a rework. The base car is the Stinger GT that’s equipped with a 3.3 litre twin-turbocharged V6 petrol engine, developing a healthy 365 hp and 510 Nm of torque in stock guise. For the GT420, that alone won’t cut it.

To modify the engine, Hyundai Europe’s powertrain team recommended HKS M45il spark plugs for enhanced combustion, a K&N sports air filter and a cat-less lightweight Milltek Sport quad-exit exhaust system. This saw outputs get bumped up to 428 hp and 560 Nm of torque.

A six-row automatic transmission cooler is fitted (in place of the stock four-row item) for better cooling, and the transmission control unit has been recalibrated for quicker shift characteristics in Sport and Sport+ modes. Once that’s done, it’s time to strip the car out, because any racer knows that lightness is crucial in a race car.

Everything that makes the Stinger GT a proper Grand Tourer has to be thrown out. That means the seats, seat belts, airbags, sound system, interior trim, rear window regulators, engine cover, underbody covers, parking sensors, boot and bonnet dampers, as well as rear bumper beam and foam were chucked, while the rear windows were glued into place and lightweight door cards installed.

A steel panel replaces the sunroof, but a honeycomb panel was grafted to improve reinforcement to the panel. In total, approximately 150 kg has been removed, but this is after the installation of the custom-built roll cage, lightweight Sparco racing seats with harness, and fire extinguisher. A Lite Blox LiPo battery completes the weight reduction phase, shaving off 22 kg from the original battery unit.

Elsewhere, the Stinger GT420 gets wider OZ Racing Leggera rims (saves up to five kg per wheel) shod with mixed-profile Pirelli Trofeo R tyres, and behind each of the front wheel rests a six-pot Brembo calipers with 380 x 34mm rotors and Endless pads, and racing steel flex pipes. To maximise road adhesion, the front cross-member was modified to increase camber angle to -2.5 degrees.

At the back, the Stinger GT’s standard brakes were used, although all corners get augmented with cooling ducts and deflectors for maximum cooling capacity. The shock absorbers are standard as well, although conventional dampers now take the place of the adaptive dampers. Each absorber gets an Eibach Pro lowering spring, while a pair of front-mounted 25-mm anti-roll bars and 17-mm units at the back help improve vehicular dynamics.

The car’s ABS, traction control and electronic stability control have been optimised for track use as well. Kia says the Stinger GT420 is easy to drift, particularly in Sport+ mode and with the traction control and electronic stability control completely disabled.

Lastly, to give the Stinger GT420 a racier look, a Stillen front splitter and rear diffuser were added, along with a rear spoiler by Air Design. But the final pièce de résistance is the eye-catching livery that integrates nicely with the existing HiChroma Red paintwork, adding white and graphite grey elements. It’s unclear how much it cost to build the Stinger GT420, but looking at it, we can’t help but long to be in the driver’s seat.