こいつら耳が早いな。 "These guys have quite quick/fast ears" rofl
Meanwhile, some people already made some MAD video about Rewrite possible Opening/inserted song:
http://www.nicovideo.jp/tag/rewrite
I dunno why, but some choices are quite fitting... perhaps gutfeeling with that picture ^^
(duh... i'm already in love with Lia's "Karma" song XD)