I had my pitted windshield replaced last year. I removed the front fenders, and brought to a local glass shop that had done at least one prior GT. Really not sure how a good job could be done without removing fenders, and the fenders could easily be damaged, removing the old windshield. I would pay special attention to how the seals on the sides of the windshield are reattached. The glass shop used some double sided tape, that was too thick and made the seals not lay flat. I ended up redoing them, and got them back to a factory look. You can replace the seal, but it goes all the way around the top of the door. I bought a new u-channel, as I believe it was called out in the Ford service manual.