How do I convert my XM radio (That came with the vehicle) to Sirius? I've heard there's a converter or something that I can buy. The vehicle has an in-dash Nav system and the XM is installed on the same screen?
Any ideas?

SIR-GM1, http://www.tss-radio.com/sirius-connect-p-228.html?osCsid=2f95c60f9b07c7b6da143ac7562d32dc fits most GM vehicles. Check the list for yours. You did not say what kind of car you have.

Chuck the XM in the trash and just get a new Sirius recirver. Why bother with all that crap.