I have an SL2 and RadioClassics is working fine through the WiFi. Not only did they add RadioClassics, but if you get the best of xm they also added a couple more sports channels as well as VIRUS to the WiFi.
My only problem with my SL2 right now is that it is not showing the team logos on the best of xm sports broadcasts. I like hockey and it kind of sucks not seeing the logos. It is also missing logos on the NBA games.