Ok, just hear me out...
With a CD, why not mount the main unit in the rear window, following all of the normal parameters, with the controls knob facing in towards the cabin area?
If someone was willing they could even set it so that they could see the arrows in the rear view mirror, and eventually memorize the various tones. Not sure how it would be trying to read the bogey count though.
I'd think that without too much trouble one could make it more stealthy to LEO's as opposed to having it mounted somewhere in the front.
It also might be less apparent to theives as well.
Maybe a tad more work, but what do you think?