I've installed 2, Yes the screw IS necessary, it holds the ends down just not the ones it comes with. They need to be a 1/4" shorter and I would recommend using a wider tape as well as Auto prep surface cleaner it's a wax, grease etc. cleaner. If there is any wax on the surface the tape WILL give. Also install it on a warm day, that way the plastic will conform to the roof easier.[8D]
