I think in another thread it seemed the Crossfire has both MAP and MAF Manifold Air Flow, strange if it's true.

MAP can be just as important on a NA engine as forced induction one, I suppose you could think of it as a measure of how much air the engine is trying to suck in - and so an indication of how much fuel is needed.

Actually I don't think it is essential to use either a MAP or MAF some systems seem to use just a wideband sensor, throttle position and rpm - they are not exactly tuned for economy or emmisions and usally run very "lumpy" cams that MAP sensors struggle with.