You've probably noticed that when the sun is coming from the side, the sun visors are practically worthless. I once had a GM car with a slide-out in the sun visor to cover that bit of glass. I considered putting a piece of window tint on the upper 2" of the window, but I don't know how that would hold up when I lower the window.

Obviously, the visors can't be any longer, or they wouldn't fit below the windshield. So, the choices are some kind of slide-out extension or a separate visor to put over the side windows.

 

What about a visor extender like this?

 

I guess that would work, and aside from designing a new visor with an internal slider, that's probably as good as we're going to get.

 

Or, tint the windows.