Hm, I remember thinking about a song while listening to Days..
It was Every Little Thing's Koi wo shiteiru!
http://www.imeem.com/onmyownmind/mus...i_wo_shiteiru/
So sweet! Mostly the general composition and etc. Koi wo shiteiru was composed by Kazuhito Kikuchi I believe.. so I wonder if that leaves Days open for being composed by him too?