you can have a boost leak from other then just the IC. and you have to cut the IC and TB down to get it to fit. Or source out a ver 1 ic, but those are hard to find and small. A FMIC on a stock turbo is going to be really slow. do some reasearch. you will need to upgrade the turbo/injectors before you get a FMIC, and a stock wrx turbo might not be big enough to help you with a FMIC. and then you will need something like an SAFC to controll the larger injectors. do you know if he converted it to use the ej22T ecu or is it running the stock impreza ecu? if its got the impreza ecu you will have to get something to controll timing as well or you will blow your motor up.