I have worked in multiple GM plants and, to be honest, the paint is poor. The last plant, Arlington where I just retired, has a brand new paint shop and still no real improvement in the paint. The #1 problem (and has alway been since the 90's switch to water borne paint processes) is ENVIRONMENTAL. The older paints of years gone by were easier to use and dried uniform as well as other nice "quality" attributes. The the EPA came in and paints suffered terribly in it's ability to spray uniform and dry well while meeting tough EPA laws.