rotary downshift

well i have a question about fmu 's ... ive been doing some reasearch and ive found that with a wide band and an fmu it should profide me with enough adjustability to turbo my ne motor .. not take into soncideration im using a slightly modified s4 turbo and manifold but its the same concept ill still be running low ot moderate boost psi ... can ne oen tell me what they knoew on the subject or if thie cartech system will do the trick ?