[rodneym]

I don't know of any 'tear offs' that are optical quality, although there probably are some clear tint style films. But polycarbonate is as soft as mud in the plastic world and scratches are the price for shatter resistance. Of course you could buff them out with anything from (some) toothpaste, to 'PolyWatch' and the myraid of mild cutters and polishers from auto stores.
I believe race cars use polycarbonate with a silica 'marr-guard', so you have the protection of polycarbonate with the scratch resistance of glass. It's not cheap and can't be bent much (if you're working from flat sheet) and will run at least $500. A formed and marr-guarded windshield will be big bucks. I'm sure a speed shop could help you.
Good luck and let us know how it goes.
rodneym