not worth replacing the windshield. this is the way the windshields are on the model S, sadly.
i replaced the windshield on my 21' S refresh... they messed up the car's seals and created more problems and headaches. It got so bad I had to sell that car and I got a 22' Model S and the windshield remains with the same slight distortions. Did I replace it? No, I just knew it wasn't going to fix the issue and it might lead to more problems than what it's worth. just learn to live with it and you will forget about it soon.
...as for rattles that's a whole different story *sigh*