This is on a z6 swapped into an eh4.
Bone stock on an s300 reliability tune
There is a very audible hiss around the tb/intake and I know it's not the specific intake as it will do it with open throttle body/any intake.

The obvious answer is intake friction causing a hiss. Like pursing your lips then sucking air in. But my question is, is the sound possibly something bad? Should I check my intake man or what?

NOTE: the car does have a/c and it does change the sound with it on/off. And it's only recently started making this noise

 

Sounds like a vacuum leak.
What's a "reliability tune"?

 

Very good idea on the vacuum leak.

And I had s300 Layin around so I put it on my p28.
Basically changed a/f, timing, etc to a more reliable state. Nothing aggressive though. But also not stock basemanp.