Link G4X Plug-In ECU - Subaru Impreza WRX STI 2004 EJ20 EJ25 | WRX104X

Easy to install. Affordable. Reliable.

The Link G4X PlugIn ECU transforms your WRX into a precision-tuned performance machine. Enjoy the latest in engine management technology, fitted directly into your OEM enclosure with no loom modifications required.

Choose the Right Model – Pin Check Required!

The fastest and most reliable way to confirm you need the WRX104X is to check pins A1–A3 on the OEM connector:

• Pins A1–A3 have wires → You need the WRX104X (this listing, 224-4000)
• Pins A1–A3 are empty → You need the WRX107X.

WRX104X mostly covers 2004–2006; some late-2006 cars require the WRX107X, so this check is essential.

Vehicle Compatibility

• Designed for WRX V10 EJ25 (2.5L) 2004–2007
• Manual transmission only
• Suits GD/GG chassis with electronic throttle
• Not suitable for GR/GH/GE/GV hatchback or 3rd generation WRX

Model breakdown:  
WRX104X → Mostly covers 2004–2006  
WRX107X → Mostly covers 2007 and some late 2006

Why Choose Link G4X?

• Factory fit, motorsport power – installs in the OEM case with world-class tuning flexibility.
• Plug & play – no wiring loom alterations for supported models.
• Confidence & reliability – proven hardware and software, trusted by tuners worldwide.
• Serious features – advanced boost control, antilag, launch, knock control & more.

Specifications

Click here to download the full Specifications PDF.

Documentation & Guides

Official Link Engine Management resources for this product:

• WRXLINK (04) – WRX104X installation manual (PDF)
• PCLink tuning software (free download)
• What G4X gives you (Link tech article)
• G4X Plug-In ECU specifications (PDF)
• Link knowledge base