Do not use that mount, use a visor one as shown below, or put it right above your RVM. Do you have laser jammers? If not your RD is useless, don't even bother using it in Fairfax, quite a bit of lidar around here.
Fairfax county cops don't seem to really care that much for RDs, my first cobra many years ago I had mounted openly and never had an issue. The only ones to watch out for are VSP, they use spectre 5s to look for radar detectors. Since you have a Redline this wont be a problem. I have heard they will hit you with Instant on from the rear to see if you slam your brakes, never had it happen to me. If you are ever pulled over, just say no to any searches, and what can they do? Get the dogs?