Help w/Sirius Radio

[dweise48]

I have an '05 Bird with a radio button for Satellite Radio. I would like to add Sirius but am having trouble finding the right tuner to work with this radio. I contacted Sirius and was told I had to go to Ford. I went to Best Buy and Circuit City and was told I have to go to Ford. I went to my Ford dealer and they told me that they had them for only $425, installed! This seemed grossly overpriced since tuners for other cars can be purchased for $99. Has anyone bought and installed a Sirius tuner in their Bird? What did you buy?
Thanks.