G4X PlugIn ECUs offer the latest in engine management technology, designed to easily maximize the potential from your car.  
This ECU fits inside the factory OEM enclosure. Installation is a breeze, with no alteration of the factory wiring loom required for the models listed below. 
Designed for the WRX V10 EJ25. These ECUs cover 2.5L from 2004 to 2007. 
- Please check your connector matches the header in the listed photo and check the notes in italic below before purchasing.  
- This ECU works for manual transmissions only.  
- Air temp sensor highly recommended. 
- Most factory features are supported. 
- Check the features tab for I/O expansion options  
Suitable Applications:
The WRX104X mostly covered the 2004-2006 range. 
 
However, some 2006 models require the 
WRX107X  
*The fastest and most reliable way to tell, is to check whether pins A1-3 are populated. 
*If the pins have wires, you need the WRX104X, if there are no wires, you need the WRX107X  
*Suits GD or GG chassis with electronic throttle.  Not suitable for the GR/GH/GE/GV hatchback or 3rd generation WRX’s