Fuel Injectors deliver fuel into the engine cylinders. When increasing airflow into your modified engine, you must also increase fuel. Having an imbalance of your air fuel ratio can cause lean conditions, which are dangerous for your engine. Performance Fuel Injectors will help deliver the fuel you need, and allow for more power to be made. When looking to upgrade your fuel injectors it is high recommended to speak to one of our experienced representatives who can help you make a more informative decision. Depending on your 2004 Subaru Forester, intended use, and desired power – the type of injectors needed will vary. Sport Compact Warehouse is your premier source for fuel injectors and you will find a full inventory of many leading manufacturers.