I bought a sattelite radio for work a few years ago and after using it for a short while I found that I could not listen to regular radio anymore. Now I have docking stations for it everywhere, house cars, you name it. Heck, I can mow the lawn with it on my belt and never lose signal.
It's great for the boat since it does not matter how far from land you are and it plays through the stereo with an ipod adapter. No commercials and 200 channels, not to mention the sports and news.
Sorry, I know that didn't answer your question but for less than $200.00 you can get a unit and hardware for all your vehicles. Just a thought.