I'm no expert here, though I always export vehicles for SR from Blender.
I see your artifacts are already visible inside Blender. So I'd say it's definitely an issue with the mesh.
IMO you either made it wrong way or perhaps moved vertices each own after or so.
I would recommend having more triangles, not just 1 triangle from top to bottom of glass. Makes normals go bad I'd say. And also regular sizes, like a grid, mostly rectangles.
Perhaps the solution is to make a looped curve and just by F create faces, for each side separately.
Likely better to make top and bottom curves and extrude curve (to get faces), with few steps along the way.
From my side I usually have just 1 mesh for glass, two sided, not 2 glass sides/meshes culled. Could give more artifacts at least in SR.
Also you have all (edges) connected, which means moving 1 vertex affects normals nearby. I highly recommend doing "edge split" to have each flat surface separate (if not making these meshes as above).
There are few cars with glass in our SR repo: https://github.com/stuntrally/blendfile ... aster/cars
Names are the same as in our vehicle browser with previews too: https://stuntrally.tuxfamily.org/cars