I have a 2017 Four Wheel Drive Sierra with the Max Trailering Package and the 6.2L engine. I tow a 34' Airstream travel trailer (9,000 pounds loaded and about 1,000 pound tongue weight) and I get a good deal of porpoising on some washboard type roads. I have a Hensley Arrow Equalizer hitch with 1,000 pound spring bars. Also, I consider the truck under damped even when I'm not towing. I'm considering upgrading to the Bilstein 4600 series shocks F & R. Does anyone have a similar experience with this situation or the Bilstein 4600 shocks. I installed these shocks on my 1992 Suburban many years ago and I was very happy with the results.