i assume you have never taken a motor apart that has has ccv run thru it its whole life? everything i mean EVERYTHING on the intake side is coasted in a thick black oily sludge. not only does it reduce passage size but it also hurts flow. That, in turn, effects spool up and egt.
Mostly due to the EGT. Vacuum on the crankcase makes a bigger difference in performance than some oil film in the intake takes away.