my apexi power intake has that as well
like others have said its where the join is
you might be getting used to the sound
i dont heard my BOV anymore and when someone goes in my car for the first time they always ask if its gets annoying
i dont even have a parcel shelf in my car at the moment
just metal with two empty holes for speakers
if cops didnt say anything about that when they pulled me over they wont notice your missing two metal clips
all RB engines make that ticking noise on idle..
listen to a few skylines with their bonnets up and see
if yours is louder than others your lifter springs might be getting long in the tooth