I have a pair of Revo polarized sunglasses, and have zero problems reading my DarkStorm smoke-lensed Empeg. I don't remember how it worked with the standard blue lens. (It wasn't long before I changed the lens, and I don't remember whether it was installed in the car by that point...)

Does the display become more readable at some point when tilting your head a good bit to the left or right? If not, polarization isn't involved.

Alex