I have a 440 powered 73 Dart 4 dr. Assembled in 1999. I removed all the body through-holes and bondoed the holes for a slick body look. I am not a body guy and did not get a smooth surface that really showed after I had it painted. Any rust I found (very little)I cleaned to shiny metal and also bondoed.
The body has not cracked or separated as of today. I am in North Texas the hot sun is the biggest paint and body killer around here. It mostly garaged and not a daily driver.