Just swap out the XM reciever for the Sirius http://nissanipod.com/catalog....ail=1 and add a new antenna. I am not sure about the OEM roof antenna for Sirius. It is probably a different part# than the XM, but if you look for 2006-2007 (when Sirius was a factory option) you may find the part# you need.
Nissan/Infiniti is XM exclusive now. They will not even acknowledge the existence or compatibility of Sirius tuners. But they are the same as they have been for years.
