I used to have the same Sirius thru FM transmitter and the sound was not too bad on my Audi TT i had before. Iwonder if the Bose system had on my TT makes a difference. Anyway I just installed it on my X last week and the sound SUCKS !! not interference wise no problems there, but honestly sounds like a tape player ... Is there a lot of difference in sound if i get one those Sirius BMW offfers? is it a digital sound? Is it CD sound quality? Any ideas or suggestions? I have a 2002 DSP and Nav. Thanks in advance.