For what’s worth, I installed some tint that I bought from Wal Mart about a year ago. I also watched several YouTube videos beforehand. It was on a curved side window. I spent a full half hour trying to work out the wrinkles. I could easily move the wrinkles around to different parts of the window, but I could never get rid of them all at the same time. It seemed like the film had zero streachability. I left it on because the car was an old junker, but it looked very amateurish. I felt like I could have done a flat window just fine, but the curves didn’t work out for me. Maybe some higher quality film would have made the difference.