1) Weird rattle/screeching noise when at idle coming from A/C belt I think..
- tried oiling/greasing it, checking if it was tight im thinking it is a bearing in the pulley.

2) I have the moo noise but I don't know what to cover.. I have the ARC super induction Air box.. (im noob i know..)

3) boost patterns are perfect but sometimes the boost goes past -20 when i shift at higher rpm.. boost leak? can't find it..

how can I fix these problems? pictures would help! thanks!

 

heres my take:

1- the scratching sounds like a idler puller, maybe the clutch in the ac compressor. start there i assume

2- for the moo noise there are a few ways to put a muffler on it, just search for airpump moo or somthing along those lines

3- by -20 i assume you say 20 inches of HG vacuum? my car gets that as you are downshifting, i would do a boost pressure test and see where that leads you. there are many stock rubber hoses and y-pipe that crack over time. if you search for boost pressure test or something like that im sure you can find many detailed ways to do this.