East Coast Supercharging ECS Stage 2 2003+ Fuel System - Manual (Page 8)

Remove Fuel Pressure regulator from FP assembly,
using pliers if necessary.
Transfer o-rings from factory FP regulator over to
the ECS Fuel Pressure Regulator Block off plate.
(just the black o-rings need to be moved)
Seat ECS Fuel Pressure Block off plate in the FP
assembly and reinstall the plastic retaining ring,
and the factory ground.