I did a temporary install of the Roadhawk HD yesterday. It was easy to install, although the location requires moving it around a bit. I ended up with it below the rear view mirror. Initial GPS reading took two minutes, but it remembers the last GPS reading and uses that for the next trip. It appears very accurate for speed, gps, and a high quality 1080p 30Hz image recording. It worked well at dusk and into my garage with headlights on. On my S5 there is an air duct in the center of the dash, which is probably used for defrosting. This grill gives a reflection on the windshield which is picked up by the camera. Not a deal breaker, but slightly annoying. The flash card that came with it is an 8GB class 10, which will give about an hour of video, separated into one minute files. These are MP4 files which are not readable by the SD slots in the dash, due to the resolution.
Current: 2013 S5 6-speed (ED), 2016 A6 (ED).
Previous: 2008 A3, 2001 S4.