did you read my explanation of why you're supposed to use a 1:1 fpr? the idea is to take the pressure differential out of the equation and focus fuel adjmustment on using pulsewidth ONLY. the MS does not use rising fuel pressure to increase fuel. it uses pulsewidth. if you use your SFMU while the MS is assuming static pressure you're going to be running very rich. if you want to use your SFMU don't use the MS. if you want to use the MS get a 1:1 fpr. AFAIK the MS is not made to compensate for changes in fuel pressure. this is why you use a 1:1 FPR to keep the pressure difference between the rail and the manifold contstant.

here's an example:

0vac/boost and fuel pressure at 45psi.

pressure difference is 45psi.

10psi boost using a 1:1 fpr and fuel pressure is at 55psi (relative to the atmosphere).

pressure difference is still 45psi.

this makes things much simpler.

if you want to use your SFMU you're going to need to have the MS monitor fuel pressure as well and come up with your own fuel tables which compensate for the changing fuel pressure.

the whole point of the MS was so we could ditch less accurate means of fuel management such as rising rate FPR's.

-marc