This information came from "jfb" a Corvette forum member. He is supposedly an electrical engineer from Cincinnati, Oh.
"I would like to add that the Escort 8500 will NOT alert at a longer distance than a V1. This has been proven by independent tests. I know it won't because I built the calibrated microwave test equipment for Valentine Research Inc. and I have seen every radar detector tested for the minimum signal they will detect at and the V1 beats every detector out there. The reason is that Michael Valentine is a fanatic (his term, not mine) and he has always wanted the most sensitive radar detector available. As a matter of fact, the Escort 8500 comes very close to the sensitivity of the V1, but only because they are illegally using the Valentine patented frequency mixing scheme of the V1, Escort couldn't find a way to do it otherwise. I asked Mike why he didn't sue Escort, and he said the expense is very high and the outcome is in the hands of people that are not technically competent.
When you increase the sensitivity of a radar detector, you also alert on services that share the police radar bands, mostly door openers in shopping centers. Microwave door openers don't look any different that police radar guns (except for some really old door openers)."