installing an overhead monitor in a 08 Envoy last year 6 miles on the odo. headliners are very rigid and hard to cut. I changed the blade in my razor and thought to myself "I hope I don't cut myself with this fresh blade." first cut, slipped out and almost gashed the back of the front seat. second cut I moved my lefty up a little bit to help keep from going into the seat, righty slipped and bam! right into my left index finger, all the way to the bone. Good thing is that i didn't get even a single drop of blood on the light tan interior.