when I shift gears, it sounds like i can hear a low sounding bov, is it normal? i dont have one except for the stock one. is it the stock bov sound?
Sometimes the hose connecting the intercooler to the throttlebody gets loose and the turbo/ bov is more prevalent. Check that and adjust as necessary
did you install your downpipe recently? I noticed that noise was a lot louder when I went stg. 2 due to less heat shielding etc...
^ well if you're stage 2 you would be pushing more boost, which means more pressure in the system to get recirc'd... the bpv will be more audible. i noticed the bpv was louder right after i went to stage3 on the wrx and stage2 on the sti. but it couldn't hurt to check your hoses too