Recommendations for suspension mods on a new truck

I beleive you could put 4500lbs in the back of a new dually and not “need” a thing to haul it all day long.
That’s also a moot point. New 2500-5500 trucks will blow away the old iron in every conceivable aspect except simplicity.....and they’re not that much more difficult to work on imo.
I love older trucks but the comparison isn’t apples to apples. Things change.