Okay, anyone know details about this song, "Aoi Shoudou" (Blue Impluse)? It says it was done by Naoki feat. Yuki, but that doesn't tell me a whole lot. Is there a longer version of the song than the 1:50 minute long version featured in the game?

That song originally came from Beatmania IIDX 8th Style.  It was incorporated into DDR Extreme as part of the "From IIDX" catgeory, but I think it was modified slightly (as in, shortened; the original is 1:50 while the "For Extreme" version is 1:36).

While many of the regular IIDX artists have released full-length albums with extended songs (Akira Yamaoka, TERRA, TaQ, dj TAKA, L.E.D.), I don't believe Naoki has done so (other than his work with BeForU).  As far as I know, there is no extended version.

TЁЯRA is Naoki. ^_^  Well, technically it's Naoki + jun. There is a lengthy Sota Fujimori remix of "Aoi Shoudou" on the TЁЯRA album, though it has jun doing the vocals instead of Yuki: http://www.youtube.com/watch?v=7TB94vcayqA

As for the original, there's a slightly extended (2:07) version on the nonstop disc of the DDR Extreme soundtrack. However, I think they just cut and paste parts of the song.

Thanks for the info, guys!