If I remember correctly a USB drive of a tachikoma came with this release which had extra music and omakes
http://en.wikipedia.org/wiki/Music_o..._Alone_Complex
Paraphrasing from wikipedia
Stand Alone Complex O.S.T.4 is the fourth original soundtrack of the Ghost in the Shell: Stand Alone Complex anime series, the album was released in Stand Alone Complex CD-BOX, which includes the first three Stand Alone Complex soundtracks, be Human album, and the Solid State Society soundtrack along with a Tachikoma-style USB memory stick featuring previously unreleased music from Tachikomatic Days, as well as voice clips, images and video.