my cls has no audible alerts for safety camera's,so decided to purchase a dash cam with alerts,spot on snooper dvr-4 also has forward collision warning system,lane departure,wi-fi,normal camera function and other bits and pieces,only down side user manual is on computer.had it wired to ignition system as I didn't want to run the battery down.only used the speed camera function to date mph is different from speedo about 2mph so will compare with tom tom as well and get an average.has anyone else tried this?