You could make your own and save a few bucks. Get some polycarbonate from a home improvement ware house. I think it needs to be 1/8 thick to be NHRA leagle but I would check the rle boox to make sure. Trace around your old windshield then cut it out with a jig saw. Then screw it on using counter sunk screws.
I used lexan the same thickness as the stock windshield, put it in the stock weatherstripping without screws. The best part is it looks stock but lighter. I've went 150 mph and had no problems with this combination. Its been in the car 10yrs.
I hate Lexan windshields, they scratch easily unless you buy the MarGuard which is even more expensive and the glare at night really bothers me. I have a hard time seeing out of it that's why my car has real glass all the way around. It's really not that much heavier if you look at the big picture. Even if I put all Lexan in my car I seriously doubt I'd save 50 pounds.