As someone who has polycarb hanging off of their face every single day, allow me to add my opinion:
Don't use it as a windshield. Definitely not on a street car.
Why? Because it gets scratches in it if you look at it crosseyed. (Which sucks in a pair of glasses.
) OK, you actually have to have something touch the lens. But "something" in this case can be a paper towel. And yes, the lenses are coated in a scratch-resistant coating.
On a street car, this means that every swipe of the windshield wipers will haze the window. It might take five or even ten swipes to have a noticeable effect. So that's about 15 seconds of driving in the rain...
A track car that gets towed in an open trailer will probably have noticeable flaws by the time it gets to its first event. At least, if the track is more than three hours away... A cover will, of course, haze up the entire windshield in an hour or less.
A track car that is towed in an enclosed trailer would be fine. Just budget for an annual replacement of the windshield.
OK, I am exaggerating--a bit--above. But I don't really think polycarb is a great material for a windshield. A Ginther-style shorty windscreen, hell yeah! Glasses, OK. (Real glass in my prescription would be
thick.) But not a real windshield, at least not for most 914 folks.
--DD