|The opening and closing of your fuel injectors causes fluctuations in fuel pressure. The role of the pulsation damper is, as the name suggests, to dampen the fluctuations caused by the injector pulses ([ http://www.radiumauto.com/Blog/Post/Radium-Fuel-Pulse-Dampers-90 ])
A fuel pressure regulator is not a pulsation damper (unless you’re referring to one of a handful of aftermarket FPRs available the explicitly include this mechanism in their construction) but some aftermarket regs do a better job than others (https://adaptronic.com.au/blogs/articles/fuel-pressure-regs-is-there-much-of-a-difference).
Bigger fuel injectors will cause wider oscillation.
Can you delete the FPD on your factory fuel system? Probably. Will the car run better? No. Will it run worse? Yes but perhaps not so much worse that you can measure it with the seat of your pants.
The fuel rail you are using has no bearing on fuel pulsation.