While it's not quite the same, one of my all-time favorite vehicle modifications is ceramic window tint on the windshield. The highest quality films available today are amazing at heat rejection, block the UV (no cracked dash in 20 years!) and are clear enough that you can't tell it's there.I’m still waiting for a good sunshield lol
Saves you the hassle of storing and fumbling with a shade, and provides very good heat reduction.