You can create as many as 4 Radio Stations for each profile. The main folder must be created in the user’s profile storage:
“My DocumentsTest Drive UnlimitedsavegamePROFILE_NAMERadio”.
In it, you can create upto 4 folders (the folder name will be the Radio Station
name). This is where you can edit your station tracks, there are four kinds of
files allowed:
- MP3 audio files.
- M3U play list files (the M3U file must be created in this folder otherwise it will
not work; the file will not work in-game if it is copied from another location to
this folder).
- Shortcuts to MP3 audio files.
- Shortcuts to M3U play list files.

Hope it was useful