Wouldn’t the tempered glass/screen protector cause the ambient heat not to dissipate quickly as it should and cause the screen burn in?
When you park your vehicle directly at the sun, the dashboard will be exposed to direct sun light and will be of high temperature. Using a tempered glass will keep part of the heat from dissipating away further causing damage to the screen over time due to burn in.
i got a tempered glass for 150 from Amazon. the screen looks absolutely clear, no dimming out and it works just fine.
the only problems are a few bubbles, which is because of my inexperience at installing them. the installation tools might be the only reason to go for spigen!