The IAG Performance Fuel Line kit is designed to work with the IAG Top Feed Fuel Rails and OEM FPR (Fuel Pressure Regulator) for 2004-2006 STI that has been converted to top feed fuel injectors. These braided lines are larger in diameter for increased fuel flow. They include all clamps and fittings to mount to IAG Top Feed Fuel Rails. IAG Recommends installing these lines in a parallel configuration for optimal fuel flow to all cylinders.