[T.L.]

cars nowadays are made from <1mm thick steel, to make them light for fuel economy.
Years ago they were 1.6mm. I have a 1982 FJ40, you can hit the panels, they wont move and you will have a sore hand. I'd imagine a hail bomb to shatter into a million pieces upon hitting the 40!. Trees branches just leave some nice bush pin striping along the sides, but nothing is dented unless you have a really big stack!.