Hello again. I received no response to my last post, so I thought I would try again, though with an update.
I managed to get behind the bumper of my refresh Model S by removing the frunk. Fairly easy task, taking about 5 minutes max.
I placed the GPS receiver and the Radar receiver both behind the bumper. The GPS receiver works magnificently, with an even more rapid location access compared to being behind my plastic nose cone on my prior car. Don't ask me why, but I am happy with that.
The Radar receiver, OTOH, is not picking up any radar signals at all it seems. Honestly, I am not surprised being it is behind an aluminum sheet. I will need to get a clear view, and I am guessing, that is under the bumper. This is a leased car, so I would need to do this in a completely reversible manner. Any and all suggestions appreciated.