Installed RAS std duty on my 2021 Silverado 1500 duramax. Pulled a 28ft travel trailer (including loan level anti sway hitch) with and without. The RAS is fantastic. Eliminated the minimal sag and distributed correct amount of weight to front axle. Steering control and porpoising completely gone. RAS is set at 40% (or 45% I forget) spring load. Will never have another tow vehicle without it. Had it installed by a local shop that was listed as a distributor for about $425. The trucks rear end rides one inch higher with no load. The one inch isn't noticeable in my opinion. Also found that the rear end is much smoother with no load over rough roads / terrain. Highly recommended!