After having the opening song of Ga-Rei Zero stuck in my mind because of its fast beat, I looked for the soundtrack, and found it on CD Japan.
The opening song is “Paradise Lost” (Track 2). Here’s the CD insert!
Track 14 is the ending song. There are also a few nice piano pieces. For track samples, go to http://www.neowing.co.jp/track_for_cdj.html?KEY=LACA-5837