358/2 days is an extreemly wierd title.
Nevertheless, the one on the psp is kh 2.5(or 0.5 since its in the past) since it continues the stories secret ending. While COM2(358/2 ) is basicly the repeat of how roxas got involved with organization XIII and so fourth. Basicly 358/2 sounds pretty good, I want to be evil, its fun as hell!