Just drilled it freehand with a collar on the bit so it wouldn't punch through too far. Then I enlarged the hole a bit and used fairly fat sheet metal screws. Don't remember the exact size, but once I got them started in the hole, I nipped off the points. The screw tips are probably no more than two threads in, but it's held up fine.

One thing to be careful about is the screw head shape. I got lucky and the screw heads are just right to provide friction against the V1's top and hold it in place.

 

+1 on this set-up. Works great. Sits just low enough to also provide clear line of sight for rear window as well. If I leave the car parked for any length of time, I just disconnect the wire, tuck it over the sun visor, and remove the detector.

 

Thanks Jon!

This is my current set up, but the suction cups tend to lose their grip after a few days. More importantly, the idea of a 3/4lb. metal box flying around the cabin at eye level in the event of an accident doesn't appeal to me

 

part of the issue is that those little black dots (WTF are those there for) do not present a smooth surface for the suction cups. Just put a piece of heavy clear packing tape over the area where you want to stick the cups to make the surface smooth and Bob's yer uncle