I noticed that the sound quality on Sirius is not that great. I have a factory installed unit.
My TL had XM radio from factory and the sound quality was better than Sirius. I miss XM. I liked their channels more.
New: 12 X5 xDrive35i Premium Alpine White/Cinn Brown
Old: 08 E92 335i|Space Gray/Coral Red/Gray Poplar
Old: 06 E90 330i|Black Sapphire/Black /Burl