I have the HK audio so I have an AUX input. I wanted Sirius and I did not want to spend a fortune but I wanted a clean install.
I used the Proclip mount for my radio. It mounts the radio dock right down by the right side piller near the factory radio. I tapped into the wires that go to the cig lighter plug under the center console so I could hide the power wire.

The reason for the thread is this. When I plugged the Sirius Radio into the AUX input it played for about 30 seconds and then flipped back to FM. When I hit the mode button AUX does not even show as an option! When I unplug the Sirius the Mode button then works normally.
I went to Radio Shack and bought a ground loop isolator and an adapter and plugged it in with that. It worked like a champ!

Bottom Line: If you have issues with your AUX Input get a Ground Loop Isolator.

 

Update: While the Radio Shack GLI works fine and solves the issue it is very large and bulky (It replaces the wire between the Sirius and the Aux input) and requires adapters to convert it from Stereo plugs to 3.5mm.

I found this one on Amazon that has the correct plugs on it and is of a much smaller design (easier to hide)

http://www.amazon.com/Kensington-Noi...=pd_sim_auto_3