I have an XE CC with the 6 CD changer. It already has the buttons for satellite radio, but no brain or antenna. I would like to add these things, but I'm not sure if I can use any brand of brain (Kenwood, Pioneer, etc.) or if I have to use a special Nissan brand tuner. Anybody have any advice on this? Thanks!

Also, anybody know what size speakers I can fit in the doors and the little openings on the dashboard?

I know the doors are 6.5" speakers. I belive you can get 6x9's in the front doors with just a little trimming of the metal in the door. Don't know anything about satelite though.
M4ck