I have an XM radio in my car and it's the external device that transmits an FM signal to a channel on my radio that doesn't have anything playing on it. Now, I know you're thinking I'm wasting your time, but Sirius and XM merged so it's the same stuff.
As far as the sound goes, the treble goes down a bit and the bass goes up a bit, compared to normal radio quality. if you just tweak with the treble and bass setting on your radio you can get it to sound good. Plus, it's got so many channels to choose from, and the songs played on those channels are a lot better since they merged. Good luck!
