Anything that actually says 'high quality' is usually spam in my experience. I'm not sure about the others. If they are same file size then probably also spam. Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see) which is purely a guide for the most common spam. Unfortunately new types of spam & spam file sizes happen.

Well, sometimes artists release albums with bonus songs on them such as an alternative recording from studio or a live performance. This is especially true for older album releases that have been re-released.