I have a clarion DX515 and a long time ago i lost my trim ring, so i took this trim ring off of an ancient cassette player we had. I had to chop the bottom side of it off because my HU flips down, but after that i just taped it onto the face (thin double-sided tape on the top) and it actually looks like that original piece.
...So what i'm saying is, try to find an orig one, if not, then find a similar one and just tape it on.....its ghetto, but it works.