Audio Systems: Adding XM, audio radios, cable interface

Question
I have a 2003 Audi A4 with the Bose Symphony upgraded stereo.  Any way to add xm so it runs, plays and accesses through my existing unit?  (This would be my first choice.)  If not, what's the best option?  Thanks for the assistance./Stuart

Answer
yes that is posible  
the cd changer needs to be remove and replace with a pioneer old style xm tunner  and the audio to xm cable interface

you will listen and control the xm from the audi radio controls, and you will see the channel number
audio radios can not support text there is no way to see the text from xm

for the interface call 40-933-1065  i believe they still make the interface