When I got my Z06 back in 2011 I, too, changed the CID to a similar unit as you and also went to a smooth coupler. I did no other changes to the air induction system. Have never received the first trouble code and she runs great.
I have never herd the air whoosh you speak of nor felt the hesitation you speak of. My "Peek" runs wonderfully.
__________________
Quietly, quietly, quietly making noise. 
|