New to the NIStune scene, so forgive me for getting overly curious

I'm in process of tuning up my R34 GTT and a mixture of circumstances has led me to wondering; how exact must the base images on the daughterboard match with the ECU number?
I understand that running late version images on an early version ECU shouldn't be a problem (eg. AA560 image on an AA501 ECU)
But will there be any adverse affects if I run an MT image (AA560) on an AT ECU (AA570)?
Or in a more extreme case, run a Stagea RB25det NEO image on an ER34 ECU?