You'll probably be fine, but make sure the intercooler is gonna fit. I'm not sure what year your Froster is, but I think it was '05 when they changed the turbo/intercooler design so that the IC bolts to the turbo outlet (now facing the hood instead of fender), so an older style TMIC won't be compatible with a newer turbo (Sorry I'm a bit unsure of model years and turbo models. Just make sure it fits first =)).
^^^I think what he is referring to is the by-pass valve. You will need a an STI/WRX/06+FXT BPV since yours will not bolt on. No need to worry about getting a STI one since the WRX/FXT BPV is exactly the same (no matter what anyone on NASIOC says). You will also need the BPV to accompany it. Oh and to the original question there is no need for a tune, you will be safer with the STI intercooler.