Using this Radium fuel hanger plumbing kit is easy. First, make sure your vehicle is one of the compatible models: 2008 - 2018 Subaru Forester XT, 2008 - 2021 Subaru WRX, or 2008 - 2021 Subaru STI. Then, start installing the in - tank fuel hanger with the help of this kit. Connect the 8AN PTFE feed line from the Radium hanger to the fuel filter under the vehicle. Next, attach the 8AN rubber hose from the filter to the fuel rails and the 6AN rubber return hose from the fuel pressure regulator back to the fuel pump hanger. Use the billet aluminum retainers to secure the fuel lines. Remember, all components are safe to use with E85. For long - term use, it's a good idea to check the fuel lines and filter regularly. And as noted, it's recommended to use aftermarket fuel rails and a fuel pressure regulator. If you notice any leaks or issues, stop using the kit and have it checked by a professional.