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Subaru
Performance Build

Stage 2 Subaru WRX STI Street & Track Build

Complexity

advanced

Est. Total Cost

$12000

Reliability Score

95

Dyno Verified

Yes

Prerequisites

  • Basic automotive knowledge
  • Mechanical tools kit
  • Lift or jack stands
  • Safety equipment
  • Access to a professional tuner

Component List & Links

High-Flow Fuel Pump

$450

SOURCE PART

Custom Engine Mounts

$600

SOURCE PART

Wiring Harness Kit

$1,200

SOURCE PART

Tuning ECU

$800

SOURCE PART

Technical Roadmap

Target Specs

  • 450WHP
  • Responsive turbo setup
  • Reliable street tune
  • Improved suspension and braking
  • OEM+ appearance

Required Parts

Engine & Turbo

  • COBB SF Intake
  • Grimmspeed Boost Controller
  • Blouch Dominator 1.5XTR Turbo
  • ETS Front Mount Intercooler
  • Killer B Oil Pickup
  • IAG Air Oil Separator
  • Invidia Downpipe
  • Tomei Expreme Ti Exhaust

Fueling

  • Injector Dynamics 1050x Injectors
  • AEM 340 Fuel Pump
  • Cobb Fuel Pressure Regulator Kit
  • Flex Fuel Kit

Drivetrain

  • ACT Heavy Duty Clutch Kit
  • Kartboy Short Shifter
  • Group N Transmission Mount
  • Driveshaft Shop Axles

Suspension & Brakes

  • Fortune Auto Coilovers
  • Whiteline Sway Bars
  • StopTech Big Brake Kit
  • Michelin Pilot Sport 4S Tires

Step 1: Engine Reliability Mods

Before adding power, install the oil pickup and air oil separator. These are common reliability upgrades for the EJ257 platform and help prevent oil starvation issues during spirited driving.


Step 2: Turbo & Intake Installation

Install the upgraded turbo, intake system, and intercooler. Ensure all vacuum lines and couplers are properly secured to avoid boost leaks.


Step 3: Fuel System Upgrades

Replace the factory injectors and fuel pump. Install the flex fuel kit if planning to run E85 blends for additional horsepower and cooler combustion temps.


Step 4: Exhaust Setup

Install the downpipe and cat-back exhaust system. This significantly improves turbo response and exhaust flow while reducing backpressure.


Step 5: Suspension & Handling

Upgrade the suspension and sway bars to improve cornering stability. Dial in ride height and alignment settings depending on street or track use.

Recommended Alignment

  • Front Camber: -2.2°
  • Rear Camber: -1.8°
  • Toe: Slight front toe out

Step 6: Dyno Tuning

A professional dyno tune is highly recommended after all modifications are installed.

Final Numbers

  • 452WHP
  • 398WTQ
  • 24 PSI Peak Boost
  • E60 Blend Tune

Driving Impressions

The car feels significantly sharper compared to stock. Turbo spool comes in aggressively around 3600RPM, while the AWD system keeps the power usable even during hard launches.

The suspension setup keeps body roll minimal without making the ride overly harsh for daily use.


Future Upgrades

  • Built short block
  • Rotated turbo kit
  • Sequential transmission
  • Carbon fiber aero package
  • Roll cage for track events

Community Discussion

Comments (2)

🔧

Sarah Engine

2024-05-08

Great guide! I followed this exactly and got amazing results. The turbo setup section was especially helpful.

🏎️

Mike Speedwell

2024-05-09

Thanks! Did you use the same ECU tune I mentioned?

🏁

Alex Track

2024-05-07

How much does this setup typically cost? Thinking about doing something similar.