two factors with my car that effected boost when i first put stg2 on it wouldnt boost over 16 psi but the more i drove it the ecu seamed to be learning the boost curve and within about 2 weeks it was consistently at 18 to 19 psi peak. the other concerning weather i noticed that i would lose up to 3 psi depending on weather conditions but power felt the same regardless of boost levels.