Audio Systems: XM interface swap - 2006 Buick Lucerns, 2006 buick lucerne, buick lucerne


Question
I have a 2006 Buick Lucerne with fully functional XM radio subscription and just got another 2006 Buick Lucerne that does not have the XM in it... YET...  
I would like to know what is required to move the XM functionality out of one into the other?
The radios are identical and I have located the XM interface in the drivers rear wheel well of the trunk in the car thats equipped with XM.
Can I move that small black box to the car that is not yet equipped with the interface?
I'm assuming that the harness is put in every vehicle but have yet to reach down into the unequipped car to see if the wiring harness is coiled up and tucked away down in there or not. Another question I have is about the antenna? from an external view they have identical antennas as well.
Do you know if I am correct in assuming the harness and antenna is present even if its not been equipped with XM yet?

Assuming the wiring and antenna are installed and are just in a dormant state, Do i need to connect anything behind the radio once I plug in the XM interface box?

Please help me with any knowledge you may have that can help me with this project. Its something I want to do Xmas night for my parents... My dad travels and loves XM but dosent have it in this new car, He gave the one with XM to my mom and she is rarely in the car at all.)
Thanks in advance for any assistance you can provide, and please feel free to email me if you have any questions for me.
Happy Holidays
Pho


Answer
Radios have to be the same, look for CAT button and  the dash under the pressets
the antenna and wiring for the antenna is in the vehicle, you need to move the  xm tuner and the cable from the factory radio  to the xm tuner,
this is the small 12 pin plug in the rigth side of the radio ,
good luck