I have received two activated SL 100 Units. They both get Stern and all the other channels along with Internet Radio, No XM I think..
I'm Considering whether to install one in my car and turn the other one into cash.
I had XM in a rental Car I got from advantage last March ('08 Sonata) Worked Awesome even in the middle of the grand canyon and in Black Canyon (Hoover Dam)
This is more of a toy thing another gadget in my vehicle. The FM Direct Kit looks like the least painful method for using on my Alpine Head Unit (iDA-X200) I'm an iPod Freakazoid. After installing the Alpine I tossed out all my burned CDs.. Local Radio is OK but the commercials too many and the songs are too mixed. My iPod(s) are great but I get bored with that too sometimes.

With the FiOS Router/Modem I use the Stiletto Like a walkman it's different. After 4 years of iPods it wasn't stale...