belts for sure. Unfortunately, I am extremely experienced in this area. It is a DSM thing, these damn belts screeching...
1) pulleys could be put in BACKWARDS (as was mine, though the difference was only 0.05mm, no more noise after dealership put it in correctly).
2) bad quality belts. Recently replaced belts, guy put in some new brand with cross-thacthed belt tread pattern unlike the regular OEM stright-lane grooved belt. Screeched like a MOTHERF(ER no matter what adjustment was made. Most likely the AC belt and the power steering one. Put stock belts on, problem solved, no problemo, hasta la vista, BAYBEH!
3) belt tensioned incorrectly. Usually solved the easiert, tighten or untighten accordingly
4) buy a Honda. Pick this one if you wanna get shot.
hehe (for legal reasons, I must put here that I was
just kidding about getting shot.