Fuel Pulsation Damper (FPD)
Oscillation of fuel caused by injectors opening/closing can be detrimental to the injectors performance and can be a performance/data glitch, that can be very difficult to get around. Fuel Pulsation Damper (FPD) is a diaphragm unit that can absorb pulses/waves in the fuel delivery system caused by fuel oscillation.
Some after-market fuel regulators incorporate this technology into the regulator. Aeromotive are one such company, but I am sure there must be others. Even if you have an after-market regulator with built-in dampening, it ideally should be mounted as close to the fuel rail(s) as possible, to avoid the need for an additional damper.