I have one made of Lexan that mounts to the under lip of the bumper, so you can take the bolts out and not have any visible holes.
It's for my Kami bumper tho, but I'm sure it would still work for OEM bumpers.

__________________

 

I did pretty much the same thing as Yanki01, but I set mine down low on the bottom grill, I also set the plate a little lower than my front lip, so that it scrapes before I hit the lip on my car, I use it as a feeler.

 

i trimmed my license plate so it fits in my lower grille and just zip tied it right on... i sort of like how it looks ive been pulled over so many times for running without it its not worth it to keep it off