Jeff-
When I bought my PRO-7, 85 RX-7 it came with a cracked windshield and the replacement estimate was $100.00 to remove, $100.00 for the windshield itself and $100.00 to install. So I removed the windshield myself and then cleaned up the seating area around the windshield frame. Installed approx 5-6mm thick self adhesive foam onto the windshield seating area. Sticky side only on the side of the windshield seating area. I then made windshield clips. The clips also have the same foam on the area of the clip that touches the windshield. The clips were then attached with thread inserts to the body and screwed into place. This allows you to screw the clips down to your torque values. When using a rivet gun you can possibly crack the new windshield.
Now when I crack a windshield I only have to pay for the windshield and it takes about 15 minutes to remove and reinstall. With this setup I felt the rigiditiy of the car was still there with a full cage but I would not do this on a street car. I have also raced in the rain with no leaks.

Duane