Ed, wasn't it something like 1.8 bar my 820's maxed out.
The standard fuel rail is perfectly adequate to supply the fuel necessary for 2 bar, it actually has a slightly bigger capacity than the better looking billet alloy JGY fuel rail.
The other thing is that as long as your injectors can supply the fuel at the fuel pressure regulated by the standard FPR there would be no reason to adjust the fuel pressure.
Imran, if your serious about acheiving 2 bar boost, if I were you I would look for some 1000cc injectors and strip out that FSE regulator for a standard or Nismo one.
Personally though having been very close to 2 bar on that turbo I would suggest taking it to about 1.7-1.8 bar max as the car become dangerous and undrivable on public roads at anything over that sort of boost. So go back to your standard FPR and keep your 800 injectors and see what boost they will take you too.....................