I decided to take my car out for a little fresh air. Damn this thing is fast .
Following a few suggestions to adapt the GIAC to the plenum I drove a bit more assertive .

What I hear going from third to forth is the sound of air - only for a moment when letting off the throttle -almost like a mild blow off valve sound of "pfssssss" . Is that normal ?

When I got home I tested to see if a few warm engine revs would emit the same sound. It slightly did , but less .

The car idles great. Moves incredible. No sound first to second .

I do have tgis large Werks1 intake and plenum and I'm just wondering if the car is simply breathing .

Thanks for any input .