There is not an IAT sensor on the SR20DET.
The boost control kit should wire into the PowerFC and you should be able to get (crappy/no) instructions from Apexi, for the PowerFC and the Boost Control kit.
Mount the IAT sensor on or near the Intake Manifold.
This should be a little helpful to you.
http://andrewmcc.com/powerfc-faq.htm
I was unable to find a pinout in my little time of looking.
Good luck.