Had my screen done a few months back with Sheilas Wheels (Esure) I HAD to go through Autoglass as they are the recommended installer/repairer. Prior to booking an appointment, I requested a genuine screen with the following - the 2 Side windscreen trims (they will break no matter how careful you are) windscreen clips for the trims to clip in (again they are brittle and snap easily) and a brand new rain sensor pad.
3 weeks later , Autoglass called me to book in an appointment as Esure approved my request. As I work on cars in my spare time, I removed absolutley everything prior to the installer turning up. All he needed to do was to remove the old screen and fit the new one.
He had on board the parts (genuine) and gave me the trims and clips but he didnt have the rain sensor pad in which I had a few spare genuine Lexus ones in my tool box so no drama.
He agreed with a genuine windscreen as he said there were a few screens hes fitted in the past that was obviously cheap and they were "wavey" when you look at it from certain angles.