I made a roadtrip on an interstate highway. Going down from my city ( I live at 900-1000 meters height city ) to a 500 meters city the red paint hold the heat and exhaust fumes mixture. I didn't need to give a lot of gas to the car though.

But now, going up for 1 hour, 80 MPH average when I had to give more gas and produce more heat due the hill, the paint didn't hold

what to use now ?

I have heard powdercoating