Well I decided to part with the MagnaVolt which was boosting the fuel pressure, or at least attempting to stabilize it. It was unable to increase the pressure beyond what the ECU was calling for (59psi) but it was able to stabilize the pressure which thus would keep the 390 injectors pumping out enough fuel,barely.
I didn't like the complexity of having to try and tune around this apparatus and it fueling increase only under boost, it just added another damn thing to try and consider when tweaking the system...so avoir MagnaVolt.
I got some custom 550 injectors from the Fuel Injector Connection. they are Ford long body injectors apparently from the Cobra, and punched out to 550 then flow matched. they cost roughly $250.
These injectors seem to be perfectly compatible with the car. Idle is good I have not noted any issues.
...still working on getting the tune right, thanks to Mike Mann for the help in that area.
