[Christ]

The glue on them "sets up" hard as nails, and the plastic gets brittle with age. It makes it fairly difficult to remove the pieces after extended exposure.

I'd probably peel it after testing if there isn't a defined effect from it. If there is, I'd most likely still peel it and see about making a foam plug for the upper grille block and maybe either moving the turn lenses forward in the bumper cover, or making a thin lexan cover or similar.