Some whistle or sucking noise is normal with a CAI. When I installed my CAI it would make a slight whistling sound on moderate acceleration (sounds like when you try to whistle while inhaling), after installing a tb and plenum it became more of an audible "shoop" noise, which is normal. My idle seemed like it was out of whack as well right after installing the tb and plenum, but as long as your IAC is working right, the idle should be adjusted back to normal.