i take it you have a silver mk4 golf then with the normal black trim on the bumper lowers.... they just un screw/clip remove them, thake them to your local body shop and ask em to flat them and prime and paint, then collect em when dry and refit... easy ...
paint shop prices vary like feck though.....
unless you wanted to buy some different ones in which case i havent got a clue!! lol
my mk4 is black so ive never bothered as they dont look bad, but i can see your point!!