I read a lot of posts at this forum about the "loud screeching" noises in mp3's. Here's what I think causes it and how to prevent it.
When whoever is putting this noise into the songs gets them in Kazaa, this is what I think they do. Download the song. Fill it with noise(the whole track maybe). Then when you download a file from multiple users of the same file size and mp3 length, parts of it are picked up from the person who has the one with screeching.
To avoid frustration and time, When you search for something, look at the file name at the far right column. If there is a number (ex. 235, 601, usually 3 digits) it usually means the file has the screeching. I don't know why there's numbers though.
If you have anymore thoughts, please post!