BMW E9X E8X Low Pressure Bucketed Fuel Pump Expansion Modules (Stage 3-4)The Precision Raceworks BMW E9x E8x Low Pressure Bucketed Fuel Pump Expansion Modules (Stage 3 4) are designed for customers looking to run all blends of E85. All pump options below include Genuine Walbro 450, Walbro 525, or Walbro 535 fuel pump(s) capable of flowing up to 350% more fuel than the factory fuel pump, and all options are 100% E85 compliant. These expansion modules require customers to already own a Stage 2 or 2. 5 Precision Raceworks