and no u dont need a rrfpr with a SAFC
depends which fcd you have.
if you have a greddy or a jam fcd, then the air signal voltage will always be clamped at just under fuel cut,
the safc alters this voltage so if the safc tells the ecu to fuel more, it wont cos the fcd is clamping the voltage.
so it would probably be better to run an rrfpr slightly rich and trim it down with the safc, also makes it safe that way incase the safc breaks.
it a similar story with the hks fcd also i beleive
i may be wrong, but seems logical to me