I used to have a metal frame on the back of my Insight. One of those "My other car is a..." ones. Trouble is the frame is taller than the area for the rear plate so it ends up scratching the paint off of the rear bumper and the plate didn't fit into the tabs on the bumper. If I were you i'd go with a black plastic frame type to be easier on the paint.I was actually interested in covers or frames that owners liked.
Can you come over and put mine on because those are the same kind I got. But I can't make em fit right. It's like the license plate is too big.For my front plate, I got a clear bubble shaped cover like this one to hopefully improve aero. I tapped the plastic plate holder and secured plate and cover with stainless button headed metric screws. (It's all in the details you know.)