I painted some portions of my grey interior black by just using kryolon fusion for plastics. The chance of matching the black perfectly is harder then it sounds and to help it match I simply blended the paint a little above the black/grey line I was painting. After I ha the area covered with paint I just removed the masking tape and then sprayed a light layer of paint up to maybe 4" past the black/grey line. That was 3 yrs ago and I have not noticed it myself.