Mushihime-sama Futari Ver. 1.5 won’t be region locked, which means you can import it. "So for this time, as a test, we’re going to make the game region free so that overseas users can play it,” Makato Asada told Kotaku.
Cave is gauging the amount of overseas fans with this test. The result (not sure how this is going to be quantified) will determine if Espgaluda II gets localized or not.
Play-Asia is selling Mushihime-sama Futari Ver. 1.5 for $68.90. You might want to get stock up on Japanese Xbox Live points with that too just in case Cave plans any DLC packs.