I have an LS430, so I don't know exactly how helpful this is going to be to you, but it might give you an idea of possible mounting locations in your SC. First picture shows the external microphone mounted above the rear view mirror, second picture shows the display screen hiding behind the shifter as well as the microphone above the mirror (which I forgot to circle), and the third just shows the display screen and the "remote" (also forgot to circle). The remote is two pieces: a flat "dock" panel sort of thing that the actual remote slides/locks into, and the remote itself. The dock panel is stuck to the wood under the shifter with a strong adhesive strip.

Note: The wire you see hanging down on the right side of the second and third pictures is not a part of the Parrot system... it goes to my dash cam. I had just gotten the car back from getting it detailed and hadn't tucked the wire back in place around the edge of the windshield and dashboard yet...

 

Thanks for posting the pictures, that helps.