Insert Credit has the scoop on Silent Hill 4 additions:
A different sort of audio CD is being included with the japanese release of Silent Hill 4: The Room. This time it’s to be a series of horror stories by Ryuzai Sadamizu (?), set to original music by the creator of the OST. Sadamizu is, according to the itmedia report, a living national treasure. This CD is not currently planned for release outside of japan.
Hopefully the Western versions will include something similar.