you are going to buy full track, but it is divided in four stem files (for example: drums, ambient, vocal, leads). you can download free program to create this kind of files here: http://www.stems-mus...m-creator-tool/
I did it once with my track, just to try (it's created by NI and compatible with Traktor), it's real fun, but unfortunately there is no psychill tracks created in this format
but I think it give huge posibilities in remixing! wish to have psychill tracks in this format to play sets. I think Rinkadink play his own track in this format with two D2 traktor controllers.