The only way to make paint gas proof or wear resistant is to clear it with a two part uerathane clear. for years it could only be applied by spray guns or air brush, but now you can buy it in a spray paint can.
Both parts come in a can and you have to break the seperator with a supplied key... once you do that you shake it and have about 8 hours to use it up before its no good.
Dupont sells it online, however most autobody supply shops also carry it.
I use 2 part uerathane clear on motocycle tanks and plastics. $100 will get you a gallon of quality stuff. Harbor fright sells small touch up HVLP guns that will work with most compressors, just be sure you have a regulator and water filter on it.