I have the Scion Headunit with the Ipod hookup, and the hu says satellite radio ready right on it, in order to get Sirius satellite radio, do i just have to call and get a subscription or do i have to get an antenna of somesort still installed into my car?

Like i said i have an 06 Tc with the factory radio with ipod setup.

both.

thanks, where do i get this antenna or whatever.

thanks, where do i get this antenna or whatever.
Here's a link to the kit (http://www.trdsparks.com/displayparts.php?Mdl_dtl=474&Part_cat=25&parts_id=754), and there's a link to the install PDF on that page too.