I haven't seen an appreciable difference between windshields, except price.

There have been a few threads about 240 glass, where it was rumored that the aftermarket glass had distortions and imperfections. Well... most of my cars with Volvo glass have had distortion, but it was only because I took the time to look for it.

To be honest with you, I think if they plastered "Volvo" on all of the aftermarket glass that is out there, nobody would ask any questions. It's just the aftermarket brand names, PPG, Viracon, etc., that raise eyebrows. But it really isn't necessary because they dont' exactly sandblast themselves. I haven't noticed much difference in wear patterns... but that's just me.
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1992 940 wagon, low miles
as well as others.