If you dont want to shell out the big bucks for the V1 or the 9500/8500 the Beltronics i940 is practically the exact same thing as the Escort 8500 but only $165 or so. I even used the 8500 hard wiring kit so I dont have cords in the way. Works fairly well but I dont speed all too much. Use it more for situation awareness.
Escort/Passport is the same thing from my understanding. I had a Passport 6500 (or maybe 8500) for a little while back in the day. I got it for free basically, squashed a $50 debt for it from friend of mine when I was 17. lol Pretty sure it was stolen, but **** it. It worked well and they are effective to a point. Then my car got broken into while out downtown one night.
Just go the speed limit. If you speed just don't be a dumbass and go 80, not 100. The radar detector doesn't save you & everyone else from excessive speed. All it takes is that one grandma/16 year old/mom in a suburban to cut you off without knowing/looking and you are getting your car and your buddy riding shotgun pulled out of the telephone pole you got wrapped around.
You have to remember, people aren't expecting a car going 100mph to be coming by them, and they don't plan or understand to look far enough back to see this.