I used to have one which I spray painted... It took lots of coats because more paint goes through it than on it. It started to flake off in some spots after a little while, but that's probably because I didn't use primer or clean it real well before I painted it.
Mine was painted white to match the car, but I took it off because it looked better unpainted. I also had to cut holes in it for my fog lights and that looked kinda ghetto.