Hello! ːrikː
Steam has added the ability to separate soundtracks from other kinds of DLC, so I am in the process of figuring that out now. If you own the DLC already, you should be able to view it in Steam and have a new "download album" option. This will give you access to [b]all-new extended versions of every track, as well as the three tracks unique to the Special Edition![/b]
The tracks are currently 320kb MP3 quality. I am working on making FLAC versions available too. The art book is still included; just choose to "View on disc" and look under the "Art book" folder.
[b]Please note:[/b] The built-in music player in Steam will play the songs in alphabetical order instead of track order. I don't have a way to fix this, as of writing.
This whole system is pretty new, so please let me know of anything unusual that you encounter. ːred_draconː