Let me show my ignorance...I was told many years ago, never buy a car that has been in a fire..that the sheetmetal has had molecular changes to the steel itself, and will no longer be the same, relative to panel shape, painting, flexibility, et.al....Is that true or is it sand and de-rust and business as usual..? I know that the time burning/severity has a lot to do with it, and that at certain temps, metal will distort some, then a lot...Anyone knowledgeable?