I want to sand and paint my high rise spoiler so I can put it on and my front bumper cover because the paint is dull and is chipping in some places. I will just be rattle canning them as a temporary fix.

-What grit sandpaper should I use on the nose and spoiler and what grit should I go up to?
-Do I need to use primer?
-How should I go about filling in the holes from my original spoiler?

Thanks.