On YouTube there is a beautiful, solo acoustic version of "Koe" by Mami.
The song is great on the album, but this stripped down version is so compelling to me. Mami sounds so vulnerable; emotionally naked. It's very moving.
I don't understand Japanese, but the translated lyrics I have found on-line indicate this is a song about loss and wanting. To a non-Japanese speaker, Mami conveys this emotion so well through her delivery in this version. I really wish the band would officially release this on CD.
Aside from that, "Awanaitsumorino Genkidene" is a musical roller coaster. Great groove, slamming drums, punchy guitar riff, big hook, and a soaring, modulating chorus-- it's an exciting listening experience.