Interesting comments. Since I have only had my S2000 4 weeks I obviously can't comment on the quality or longevity vs Miata window but will certainly be interested to see. I figured plexiglas was plexiglas.

 

IMHO the Miata window is superior. The quality of the plastic is such that it doesn't scratch as easily. The window can be unzipped and positioned flat(and protected)prior to dropping the top. The S2000 rear window is my only true gripe about the car. Not because it's plastic, I'm okay with that, but because it isn't well designed and made of a satisfactory material. I'd trade my previously owned '95 Miata's entire top in a heartbeat for the one on my S2000, also preferring the lightweight manual mechanism over the unecessary and heavier power.

 

I believe the plastic in both cars are identical in quality, thickness and optical clarity, it's just that the Miata's window can be unzipped and dropped flat before the top is lowered. This is what gives it its longevity. See-through plastic becomes increasing more difficult to look through every time you double it over. It's the folding and refolding that is causing the problem, especially if the window has road dirt or dust on it.