It doesn't have to be insanely heavy to be strong. I had a very strong tube winch bumper on my Ranger, probably 150lbs or so. Heavy? Yes, but nowhere near 600lbs. I didn't end up having a winch in it, but either way I wouldn't make the whole combination more than 200lbs.
I didn't do anything other than running bilstein HD shocks and the torsion bars were adjusted slightly (not "cranked").