if you're going to use an arm mount, mount it inside the front part of the console like this:
Successful Installation of SiriusXM radio
keeps it within reach but you can close the console to hide it and avoid giving thieves a reason to break into the car (plus keep the clean inside look, no wires or mounts showing whatsoever when the console is closed).
also, i'm sure you probably know but if you're using the bluetooth dock you can't also use your phone at the same time. that limitation is why i went with the FM direct adapter (that plus the fact that the BT dock took forever to get to market).