Looking at Nissan's website, they offer both XM and Sirius in the Pathfinder as a $399 option. However, you can only have one installed not both. Nissan is one of the few automakers selling both systems in their 2003 line. Most manufacturers aligned themselves with one or the other. From a hardware standpoint, they probably have a headunit that can understand either system and just put in the correct satellite receiver. From what I've read the antennas can work with either system.