Oakland, don't feel bad. I was also a little confused about the OP's intent, since the 08.5/09 comes with piano black. So I assumed he meant it was for additional trim in the cabin or something. Then when I read more carefully that he had spoken to Metra, I remembered that Metra makes dash kits for replacing the radio.
One reason I have not pulled the trigger on a replacement head unit so far is that I really dig the piano black & don't want to fark it all up with some cheap looking flat black plastic. I was going to talk to a paint shop to see if they thought they could replicate the piano black finish, but now I may just call Metra instead.
