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Prowear NZ Superlap Series Spotlight: Morris Mustchin’s Subaru WRX streeter

20 May 2016


Morris Mustchin is a committed Superlap contender who purchased his 2000 Subaru WRX STI when he couldn’t even drive, thanks to a serious back operation. The previous owner made sure to terrify Morris behind the wheel of the WRX during the test drive, and, at that point, Morris knew that’s what he just had to have. There’s nothing quite like how vicious the WRX STI is right from the factory — a perfect starting point for Morris to take part in some motorsport when he could get behind the wheel. 

It didn’t take long after purchasing the WRX for Morris to begin the modifications. 
He told us: “The car came fitted with the bodykit and rear spoiler, but I put the rear roof spoiler on and installed the 10 vortex generator roof fins. The first real mods I did to the WRX involved upgrading the calipers and discs, as I managed to crack two sets of standard discs at Hampton Downs Raceway doing regular track days.” 

The original brake equipment was removed, and replaced with Brembo calipers all round with 330mm discs up front and 297mm items on the rear. Morris soon replaced the compressed springs in the WRX with a set of Tein coilovers with EDFC, an in-cabin electronic damper control unit. 

The engine was relatively factory when Morris purchased the car, but, soon after, the factory IHI VF23 turbo was replaced with a VF46 — which Morris got for a steal — and tuned with a Link G1 ECU. Now, the high-boost tune netted Morris 240kW at the wheels. 

Unfortunately, Morris bent a con rod soon after the initial engine set-up was complete, rendering the first motor useless. A rebuild commenced, with forged internals and Legacy B4 heads that received some high-flow treatment — so much porting, in fact, that when it was tuned again with the VF46 turbo, it would run out of puff at 5500rpm; a new turbo was needed. A Kinugawa T67-25G turbo was installed onto a semi-tuned manifold and tuned with a Link G3 ECU that had been upgraded to G4 software. For good measure, 1000cc injectors were installed, along with a Deatschwerks fuel pump for future proofing. The new set-up netted a healthy 270kW at the wheels on a conservative tune. Morris is still getting used to the extra power and has yet to run high boost. 

Morris tells us he has not completed his upgrade package to the WRX; he still needs to relocate the battery into the boot, install a surge tank, and have a roll cage fabricated. Unfortunately, for most racers in New Zealand, money doesn’t grow on trees, so the upgrades will come when money allows. 

2000 Subaru WRX STI (V7)


  • Model: EJ20, 2000cc, four-cylinder 
  • Block: Version 8 STI crankshaft, ACL race bearings, Pauter forged con rods, CP forged pistons with HPC piston coating, ARP case bolts, ARP L19 head studs, balanced, 12mm oil pump, MRP oil sandwich plate
  • Head: Legacy B4 heads ported and polished, Ferrea super alloy +1mm inlet and exhaust valves, Kelford valve springs, titanium retainers, Brian Crower 272-degree cams, Brian Crower adjustable cam gears
  • Intake: Version 7 manifold, pod filter
  • Turbo: Kinugawa T67-25G, semi-tuned manifold, 45mm up-pipe, three-inch twisted downpipe
  • Fuel: Deatschwerks fuel pump, 1000cc Bosch injectors, Fuelab fuel regulator, aftermarket fuel rails, braided fuel lines
  • Ignition: Factory
  • Exhaust: Three-inch exhaust system, one resonator
  • Cooling: 52mm alloy radiator, Setrab oil cooler
  • ECU: Link G3 with upgraded G4 firmware


  • Gearbox: Factory five-speed
  • Clutch: 22B twin-plate 
  • Flywheel: Factory
  • Diff: R180
  • Other: Version 7 six-speed driveshafts


  • Struts: Tein coilovers
  • Brakes: (F) Brembo four-pot calipers (R) Brembo two-pot calipers
  • Other: Front and rear strut braces, Tein EDFC controller
  • Shoes
  • Wheels: 17×8-inch Advan RCII
  • Tyres: 225/45R17 Dunlop Direzza 02G


  • Paint: Factory
  • Enhancements: WRC front bumper, 22B replica wing, roof spoiler, nine-piece air vortex generator


  • Seats: Factory STI
  • Steering wheel: Factory STI 
  • Instrumentation: HKS EVC6 electronic boost controller
  • Performance
  • Power: 269kW (361hp) at the wheels on 22psi of boost
  • Hampton Downs: 1:19.883

Driver profile

  • Driver/owner: Morris J Mustchin
  • Age: 43
  • Location: Auckland 
  • Build time: 2 years
  • Length of ownership: 4 years 

This article originally appeared in NZ Performance Car Issue No. 228. Pick up a print copy or a digital copy of the magazine below: