I painted a set with the correct aluminium color paint from Audi, came out ok. I ended up stricking lucky tho, as my local breakers had an almost new RS3 come in with massive front impact and was written off. I kept looking at the covers thinking I am sure they will fit as mine has the indicators under the housing, not a cut out in the housing.
I asked how much for the mirror covers and he said £100, so I brought them as I thought if they dont fit, I will sell them on again, but they did, and look ace.
My sprayed ones looked ok, but along side the real things, they were not "quite" the same.