From one of the 17 other XM vs Sirius threads.
Fast Freddie said:There is a module you can switch out to go from xm to sirius Its about 600 bucks. the boxes are made by the same company, just the coding on it. The box is in the trunk. You may be able to find someone to trade out with you, or buy one on ebay. If you live on the west coast, you may loose xm reception because I'm told their sat is located over the eastern u.s. and sirius's is located more over the center. I've heard many people say they lose reception on 101 or if there are mountains or trees to the east of them.