I just did this 2 weeks ago . 15" x 7" steels with no tire weighs 24.2 lbs.. 15" x 7" Weld Draglights weighs 8.1 lbs. with no tire . That's a 64.4 lbs weight savings just in rims alone . I can't speak to bumpers , though . Later, Tom
DOT cert or not, I'd suggest that it would be wise to be extra careful on roads that you're not too familiar with. One decent pothole would probably do it...and it would likely be a crack rather than a bend.
I installed quite a few sets of Draglites back in my days as a Super Shops tire monkey. Had a couple come back because 3800 pound Chevelle + pothole + 40 mph = bent wheel. Yes they do bend rather than crack.
I also remember the Hot Rod article about Scott Sullivan driving his Cheez Whiz Orange '55 Chevy across the country (1st Power Tour maybe?) He had problems with his fronts cracking but they were 3 1/2's trying to keep a big block '55 off the ground. He went to steel skinnies to finish the road trip if I remember right.