OP, why ask people on here when you are ALREADY working with your tuner.
Stop asking people here ASK YOUR TUNER. Looks like you already are. Listen to your tuner, ask him all these questions instead. You will get a lot of misinformation mixed with good information on here. Your tuner can set you straight.
PS. Update your profile as it states you have an 02 WRX . I assume you have an 07 WRX?