High Flow Fuel Rail Fitting Kit Application: BMW 3-Series E36 E46 M50 M52 M54 325i 328i 323i M3 Z3 E39 528i Description: High-Quality CNC Machined Aluminum Designed to properly supply the additional fuel needed for high performance/boost applications. For top-feed injectors. Not fit OEM injectors. Note: Instruction is NOT included. Professional installation is highly recommended.