I have the TrailAir Tri-Glide on our 2011 Seville. It did make a difference in the way it tows and with the amount of bounce we get. On our last trip out, we had a bottle of water setting on the side of the step that didn't move in a couple of hundred miles over not so good roads.
We kept the old pinbox in case we ever trade campers.
Al & Linda
2013 GMC Denali 3500HD SRW, Crew Cab, Std bed, 6.6L Duramax, Allisons, PullRite Superglide, Triglide
2011 Crossroads Seville VF35CK11