MAF or MAP to con 03 wrx ecu into thinking this 2.5 is a 2.0?

[feliz]

i have a set of dark blue 565cc injectors. is there a MAF or MAP that can make the ecu see 20% less air so baseline will be close to what the motor wants? it has a 2nd stage cobb setup on it but i may replace ecu with a stock one and keep the cobb setup for my 97 brighton coupe-22b wannabe. does the ecu use MAF or MAP for mixture control. i know this car has both stock. and don't really know why. thanks. or am i better off staying with the injectors the ecu already knows and let the ecu learn? not looking for high power. still running the stock TD04 turbo. CR may be up a point since i am running S20 heads on a forester ej255 block.