And there's an alternate version of the "Badlands" music in it, that was once posted on the Atari forums.
Also, a rip of the trailer music has been put in there, which makes this collection super-complete.
A note on why the music is different (by akula65):
The interesting thing about the MP3s is that they don't correspond exactly to the MP3s that come with the game. If I remember correctly, they have a higher bit-rate for one thing. But some are also different mixes and some may actually be unused music from the game. Here is the correspondence as best as I could make it out: