I am looking at getting either a II with the 6 speaker system or a III with the upgraded JBL. I know that the III has XM reciever already built in. What I need to know is it possible to install a sirius reciever in the II or III and have it work like the factory XM. I have sirius and really don't want to have to mess with my packages to get the best of sirius on XM.
