Tarenrack

Wouldn't cha know that literally on my way to return the brake calipers to get the core refund after one of my brakes locked up, I hear a brand new unfriendly sound coming from under the hood. I popped the the hood and looked around and narrowed it down to the A/C compressor. I figured it might be a bearing so I looked around here and other forums and sure enough thats a pretty common problem, but usually the bearing seizes up and the pulley completely stops. So I spent tonight pulling the compressor out and took it apart and the bearing still felt and sounded good, the electromagnet still looked like it was in good condition, the only thing that I could see that wasn't right was one of the return springs (the on on the right) on the clutch was broken. I don't think this is related because the sound was happening when the A/C was off. So now I'm thinking that its the actual compressor thats going bad. I found a used compressor with only 140k miles on it at a local JY for only $50 so I'm going to go pick it up tomorrow and just replace the entire thing since repair kits are more than $50.

Some notes about the sound:
It only happens after the car has been sitting for a while

It changes in pitch with engine speed

It fades in and out while the car is warming up, you can hear in the video it fade away at the end but after I stopped recording I came right back.

So my questions are:
1. Has anyone had a similar issue and can shed some light?

2. Should I keep the pulley, magnet, and clutch for spares for the new compressor?

Here is a video of the compressor and the sound(click to play):



Here are all the parts:



Here is the clutch with a broken return spring: --------------------------\/(here)