Interesting, would have thought you hold it up to the door where you want it, mark the screw holes. Pull it off, hold the light and speaker to the back and see where they need to go and then transfer the outline off the grille to the door.. ????
Maybe that doesn't work for some reason, never tried it.
I was going to add them but decided to just get some neodymium magnets, embed then in the back of the grill, and stick them to the lower door. Add the look, kinda, but avoid cutting. May try to figure out some battery operated LED light to embed with a magnetic swith to turn on when the door opens, but that's only one more wild idea I have when insomnia kicks in and I'm thinking about the project...!!!