i have an 04 forester with sti ecm and turbo, what is the stock boost pressure on an sti, what can i run safely, and how high boost untill boost cut on the sti ecu?

This topic has been covered eleventybillion times!!! Do a damn search!

14.5 psi stock as long as you have the STi IC also. Don't run more than that until you have engine management. IIRC boost cut is at 18psi.