The city I live in put up one of their free radar detector testers, aka K-band speed trailer, up on a road I travel on frequently.
I made a couple passes at it with my RX65 and V1. RX65 in highway, V1 in A mode. I did not run both detectors at once. Road is relatively straight and flat but there is a slight curve before the speed sign.
RX65 picked it up at 0.3 miles. V1 picked it up at almost 0.4 miles, so the difference in detection was probably under 500 feet between the two.
I'm hoping to get my X50 back from my friend tomorrow, so when I do I'll shoot a video of all three against the sign, if it's still up.