i replace the game BGM with SD Gundam G Generation Wars BGM. it changes the mood of while playing and better than the plain original BGM
here some of the BGMs i used
Crossbone Gundam
BGM 1 http://www.megaupload.com/?d=R6DGDV05
BGM 2 http://www.megaupload.com/?d=NMPAEEHY
BGM 3 http://www.megaupload.com/?d=JA4X9TYI
Gundam Sentinel
BGM http://www.megaupload.com/?d=WMYOSXKG
Gundam F91
BGM 1 http://www.megaupload.com/?d=INPK2N0P
BGM 2 http://www.megaupload.com/?d=VUHU4BFY
Gundam Zeonic Front
BGM http://www.megaupload.com/?d=APB63NR1
Gundam 00
BGM http://www.megaupload.com/?d=P1ZY2FFF
G Gundam
BGM 1 http://www.megaupload.com/?d=WI9H092P
BGM 2 http://www.megaupload.com/?d=3HWNKFJ8
V Gundam
BGM 1 http://www.megaupload.com/?d=KT53VHFF
BGM 2 http://www.megaupload.com/?d=ZZZ4BC9L
BGM 3 http://www.megaupload.com/?d=TUXEEL87
if you interested in downloading SD Gundam G Generation Wars for your BGM, here's the link
http://ngenerals.blogspot.com/2009/09/mp3-sd-gundam-g-generation-wars-ps2wii.html
how to change BGM in the game:
In your SDGO directory, there is a BGM folder with MP3 files with the numbers as listed on the Song List page. To use your own, simply replace the respective MP3 with your own. So in practice, if you wanted to replace the music on AEU Practice Field to something like, say, "Ash Like Snow", you would rename your Ash Like Snow.MP3 to 0024.MP3.