i know that it may be hard, but u could start off slow. just create a working radio with some jingles then, only if it is possible, maybe get licensed songs on there. like one day u could be driving in beamng and just turn on the radio and if u don't get the frequency right it doesn't work, or maybe u could use it as a police radio and send signals or recieve signals about a fugitive, and stuff like that. just some working radios considering there is antennas for example on west coast and in italy too if im not wrong. hope u liked this suggestion!
personally, my opinion would be to create a UI-sorta mod, for instance, a stable platform/interface that would allow players to upload custom MP3s, instead of worrying about licensing and all the hassle that comes with it. If one WERE to preload songs to the mod, best bet would probably be Gabester's stuff.
