i have an escort, and me and my buddy were going to get his new car, so we took both, V1 and Escort, and had them both on at the same time, the reaction time was better on the V1, but i would have to say it was a veryyyy small fraction of a second...if that, so i really dont see the extra money worth it, unless you really care where the cop will come from to give you a ticket.
all i do is when it goes off i slow down as fast as i can, i really dont care where he/she is.
heck, just yesterday it saved me 4 times
