I always thought the music during the opening credits was a new instrumental version of "Sycamore trees". I mean, it sounds very different because there is a base made of noises and many sound effects, but the melody played by the saxophone is definitely "Sycamore trees".

KalhanMnel, can you give me a link or something to the Requiem track you got, please ? It would be awesome to have the original one instead of the recorded-from-DVD version I have.