Unfortunatly, there is no such thing as a super windshield. Perfection is hard to come by. There ARE however, different windshields for different applications/needs:
Lexan windshields. Primarily used for race cars, this almost unbreakable polycarbonate (not acrylic like lucite or plexiglass, which we tend to think first) is the same stuff that (after an extensive process ) is used as bullet proof glass. It's great stuff- in my mechanical engineer capacity, I swear by it. I have also been in a race car where the stuff stopped a wheel off another car moving QUITE quickly from kissing me right on the lips. Sounds like what you were thinking of? Well, if it sounds too good to be true- then it is. The stuff performs exactly as I have said-BUT the downside is that the stuff scratches if you sneeze on it. ITs incrediably strong, but very soft (which usually go together- it bends to absorb energy rather than a completly inelastic collision. Glass, on the other hand is extreemly hard, but very brittle) Race cars get around this problem by layering it with a seran-wrap type stuff that absorbs all of the nicks, pits and scratches, and can then be peeled off- perhaps something similar could work for our windshields? Lexan is also not DOT approved, if you're worring about that stuff.
Laminated Glass windshields. These are what you will find about two feet in front of your face on most new cars. There are two thin sheets of glass that sandwich a thin layer of plastic (its called polyvinyl butyrate or PVB for short) The advantages of this method is that it's fairly scratch resistant (hard), light, thin, yet still strong enough to stop anything from entering (or leaving) the car through the windshield ( think of the PVB layer as rebar for cement-it holds up and give support for what would otherwise be a very brittle substance) The downside for this one is that it still is fairly brittle, and due to the thin, untempered glass sheet on the outside, it pitts easily with ANYTHING. I currently have what looks like a bullet hole in my passenger side of the windshield from a rock - its just shattered the outer glass layer, and was stopped by the PVB layer. We'll see how long THAT lasts.......
Tempered Glass windshields. This is the "old" type, but a good one. Litterally, its a sheet of glass that has been heat tempered by rapid heating and cooling. This makes it even harder than regular glass- and less brittle, due to the break up of the rigid crystaline structure found in regular glass. They still use this stuff in rear windows- and if you're lucky, in the side windows as well. (We dont have it in our side windows I don't think- I could be wrong on that one though; its too late and cold for me to go outside to check) This is what we classically think of as "safety glass," inasmuch as it shatters into thousands of tiny, blunt, glass "pebbles" when it breaks. If you have any experiance with older cars, you know that they rarely got the sort of "sand blasted" look in the windshields- its because they used this glass. Its EXTREEMLY stratch and pit resistant. The downside is: its heavy, its expensive, its thick, and you're trading some safety for the pits. Which is the pits.
So, there is no one perfect windshield, and, dispite how many of these damned things I've been through with my WRX already, I still think the laminated ones are the safest and best bet. I am forced to get mine replaced with the OE one because I have the windshield defroster, and on the 04's +, the radio antenna is embedded in the glass. Are there thicker, more robust versions of this laminated glass windsheeld available? Of course. If you can, by all means try it. Otherwise, keep some rainx on it, some glass polish, and don't drive into the sun!
Good Luck.
