yeah right now its on stock boost, i am sure ill be fine. I talked on the phone with a few shops and they told me ill be fine, even though the evo9 flows more air the stock selenoid (oem boost) is set for an evo 8 so the boost will still be at 19.5 psi tapering to 16 psi by 6500 rpm. Evo 9 turbo runs at 20 psi tapering to 17 psi by 6500 rpm.

 

its not about what psi it runs, its about flow. you have an '03 so an '05 hotside only is a minor step up. a evo9 turbo has the 10.5 outside(05's evo8 had them) AND also the bigger compressor side. so combine those two, its not "minor". either way just dont beat on it yet.