Several people have pointed me to the news about the car hacked with a music file

But their most interesting attack focused on the car stereo. By adding extra code to a digital music file, they were able to turn a song burned to CD into a Trojan horse. When played on the car’s stereo, this song could alter the firmware of the car’s stereo system, giving attackers an entry point to change other components on the car. This type of attack could be spread on file-sharing networks without arousing suspicion, they believe.

My question would be why try to spread it via file-sharing networks to a CD (or USB for some stereos)? How about figuring out the a station (e.g. SATCOM hacking, XM/Sirius) that a car listens to; then get within range of the car and overpower/interrupt the signal with your own?

Will a malicious digital music file fed to the stereo via satellite download have the same effect as a CD but without the need for physical access?