My truck in sig rides a tad rough when empty, but I expected that being a DRW. Even w/ 1k tube sand directly over axle (in an attempt to aid it in snow), she's still a tad rough. Added an add'l 300# tube sane behind axle and ride improved but didn't help much in snow-----oh well.
Now w/ the RV attached and 3700 pin, she rides very well. Downside is the rear suspension will BANG on downstroke after encountering a expansion joint, or pavement seam. I removed the aux spring helper brackets and that helped a lot, but still does it. W/O anything to compare it to, I figure it's just due to it being a DRW and designed to carry heavy loads thus a stiff suspension.
Noise wise, It's on par w/ the '15 6.7, but by far quieter than my '03 6.Uh-Oh which I aptly had by the diesel plates on doors:"Daddy Likes The Rattle".