Originally Posted by TopgunZ

Yeah but with the Air to Air kit it completely changes the airflow. So the red spring will make a terrible flutter. I had used every spring turbosmart offers and it sucked on my car. I ended up getting the lightest spring and had to trim off 2 rings and it still didnt sound right to me.

The flutter means the air is not coming out of the supercharger properly. The noise you hear is the piston in the bpv opening and closing. It is very hard on the valve since instead of it just closing on throttle then opening when off throttle once, it is doing that like a 1000 times more. You will eventually wear your valve out.

Also, the air needs to get out of the system or it tries to push itself back through the supercharger blades, basically trying to force it to slow down but it cant since it is belt driven so it causes unwanted stress on the bearings.