Location, location, location! Its not only the number one rule in real estate, but its also a contested point when mounting a fuel pressure regulator. There are those who believe its best to place a fuel pressure regulator close to the fuels destination (fuel rail, fuel log, carburettor, diesel or direct injection pump). While others feel its just fine to place it further away. Sometimes at the opposite end of the vehicle. Either philosophy could be correct, depending on the application.