I have been looking into fuel pressure regulators recently and there
appears to be some mis understanding out there on why you need
a pressure regulator that increases fuel pressure with boost.
The way I see it; a regulator that increased fuel pressure with boost
basically widens the dynamic range of of your electronic injectors.

Injectors have certain pulse width range limits. For example the injector
may only open with a pulse width that is at least 2 milliseconds long.
This may give enough, or two much fuel, for idle. If it is too much the engine
will burn more fuel at idle because the mixture is too rich. On the other
end the pulse width may be a maximum of 80% of the time which may limit
the fuel on the top end.

7500 RPM is 125 pulses per second for each rotor.
That is 0.008 seconds or 8 milliseconds total time available. If the injector
can only be opened for 80% of this time than it will be opened only
6.4 milliseconds. If you pules it more than that it may over heat.
That may not be enough fuel for full power. That leads to 2 injectors
per rotor so the injectors can be staged. One injector is used at the lower HP levels
and the second comes in at the higher HP levels where both are used.
This is the scheme Tracy uses.

This is all well and good as you now have a redundant system. Mazda felt that
the RX8 engine needed six injectors, or three per rotor, to achieve the proper
fuel flow over the entire RPM range from idle at 600  up to 9000 RPM with a fixed
pressure regulator.  All this assumes your ECU  is a timed injection system. In
other words it fires once per rev per rotor.

What a boost regulator does is increase the fuel pressure and flow for a given
pulse width as the boost increases. This in effect widens the HP ranges
at which an injector will function properly.