Running an external fuel pressure regulator means that you can (if you want) run one or more pumps directly to a high flow regulator and not lose a significant amount of flow potential like you do when you try to run dual walbro flow through all stock lines/stock regulator. Don't get me wrong, staying with stock regulator works fine, but it definitely becomes a restriction at higher power levels. When does it become a restriction? Depends on fuel, boost, air/fuel, etc, but generally speaking it makes sense to start thinking of this as an option north of 600 whp, and much past 700 whp it needs to be dealt with. We've also sold some setups on the "early" side to customers that don't quite need the higher flow capability but they just want to lay out the fuel system in a simple, clean, logical manner that will provide a large degree of future proofing with respect to turbo choices, etc. down the line. I.e. do it once and be done with anything they were going to throw at a N54.
See above -basically when you run one or more pumps that bypass the stock in-tank regulator, typically done in the pursuit of higher flow potential.
