To work within the very narrow parameters you've outlined around safety I doubt the steel body would be any more tolerant of a texting fool that would rear end you.......I've got sedan, they're pretty much just a shell, and cutting a door opening for a delivery would just weaken it further. Additionally, known rear end collisions with '32s have shown that the stock mounted fuel tank just in front of the rear bumper is probably more of a hazard or danger in that kind of accident. Either way, these cars weren't designed with collision tolerance in mind.