02-05 WRX Modification Minimum Recommendations
Most 02-05 WRX's by this point either have a lifetime of mileage, or are on their second or third motor. I highly recommend ensuring that all the basics are covered. Here is a list of common issues I see with 02-05 WRXs that come in for work or tuning:
- Low Compression or Bad Leakdown
- Incorrectly gapped, old, or completely wrong spark plugs.
- Failing fuel pump and fuel pressure regulator
- Boost leaks and vacuum leaks from brittle lines, torn inlets, failing couplers
- Worn factory boost solenoid
- Faulty or poorly performing sensors (MAF, 02)
- Faulty or failing ignition coil packs
In general, you want to minimally have the equivalent of a fully functional stock vehicle BEFORE you start modification.
From there, here are my minimum recommendations based on approximated power goals. Each list is inclusive of the list prior.
Stock Turbo Level (TD04 ~250whp max)
- AEM Fuel Pump
- COBB EBCS
- Quality Catless Uppipe
- Quality Catted Turboback Exhaust
- Cobb Accessport
Mild Turbo Upgrade Level (VF, 16G or similar ~300whp max)
- NGK BKR7E spark plugs gapped at 0.028"
- OEM Subaru STi TMIC or better
- OEM Subaru Dark Blue 06-14 WRX / 07+ STi Fuel Injectors or better
- ACT HDSS Clutch Kit
- IAG AOS
Moderate Turbo Upgrade Level (18G, 20G, Dom 1.5 or similar ~350whp max)
- IAG or Radium Fuel Rails and Lines
- Aeromotive FPR
- ID1050x Injectors
- Cobb SF or Grimmspeed Intake if TMIC, ETS Intake if FMIC
- ETS/GS TMIC or ETS FMIC
Reasonable but not required upgrades
- Tomei, Cobb or Perrin Turbo Inlet
- IAG TGV Delete Risers
- HKS, IAG or Killer B Equal Length Turbo Manifold
- GS EWG Uppipe with Tial or Turbosmart EWG
- 07+ STi Oil Pan with Killer B Oil Pump Pickup
- GDT Cylinder 4 Coolant Reroute
