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Prowear NZ Superlap Series Spotlight: Jason Shortt’s giant slayer

11 July 2016

Jason Shortt may have had one of the lowest-powered vehicles in Pro Open, but he didn’t struggle to lay down some of the quickest times in the 2016 Prowear NZ Superlap Series in his 270kW-at-the-wheels 2003 Subaru WRX STI Spec C.

Jason is a time attack enthusiast to the core, and his build resembles something from Japan or Australia, as it’s kitted out with some of the largest side skirts and wing-end plates in the series. 

His plan of attack during the 2016 season had been to give the Subaru as much aero and tyre as possible, and the results paid off. As you could still run a full slick this season, Jason chose to run on a set of 280/60-18 slicks from a V8 SuperTourer.

Reducing weight was also high on the priority list, so the windows were replaced with Lexan items, and the interior was completely stripped. The EJ20 was retained, but fitted with Mahle forged pistons and M&H connecting rods to ensure there were no issues out on track.

The turbo isn’t the largest, and resembled a factory item, but we’ve been told it is a gnarly unit from Roger Clark Motorsport, and at 270kW — the engine’s current output — it’s about at its limit.

Despite fielding half the power of some other competitors, Jason managed to lay down a very impressive 1:41.384 around Taupo. Once the Subaru is completed, and dialled in, it’ll no doubt be quicker again — if it doesn’t break another gearbox, that is! 

2003 Subaru WRX STI Spec C


  • Model: EJ20, 2000cc, four-cylinder
  • Block: Mahle forged pistons, M&H connecting rods
  • Head: Kelford cams
  • Intake: Pod filter, V-mount intercooler 
  • Turbo: Roger Clark Motorsport twin-scroll
  • Fuel: Walbro fuel pump, decapped STI injectors, braided fuel line
  • Ignition: Factory, iridium spark plugs
  • Exhaust: Three-inch side-exit exhaust system
  • Cooling: V-mounted SW20 MR2 radiator, oil cooler, transmission cooler
  • ECU: Link G3 with G software 


  • Gearbox: STI six-speed 
  • Clutch: Heavy duty
  • Flywheel: Lightened
  • Diff: MapDCCD centre diff controller


  • Struts: HKS Hipermax Pro coilovers
  • Brakes: Factory Brembo calipers, Pagid yellow pads, DBA slotted rotors
  • Other: Whiteline 24mm sway bars front and rear, H-brace, J’S Racing fender braces


  • Wheels: 18×10-inch Koya Racing SF01
  • Tyres: 280/60/R18 Hankook Ventus F200 slicks


  • Paint: Factory 
  • Enhancements: Drift Max front bumper, Drift Max rear bumper, Drift Max rear flares, folded aluminium side skirts
  • Other: Front guards pumped and chopped, Lexan side and rear windows


  • Seats: Racetech 4000W seats
  • Steering wheel: Suede
  • Instrumentation: A’PEXi gauges 
  • Other: Buddy Club gearknob, six-point roll cage 


  • Power: 273kW (366hp) at the wheels

Driver profile

  • Driver/owner: Jason Shortt
  • Age: 33 
  • Location: Auckland
  • Build time: Nine years
  • Length of ownership: Nine years 
  • Thanks: Smudge Signs, Koya Wheels NZ for hooking us up with some primo rims, for keeping my engine running, MapDCCD, Highbrook Automotive, and my wife and kids who are there for when it breaks.