Hi All, I just bought a new 2021 HQ-12, towing with a Tundra Crewmax, 4x4, 5.7L with Fox 2.5 adjustable coil-overs, lifted maybe 3 inches. Extremely pleased so far after our first weekend out. I noticed that when the tanks are 100% full (freshwater and drinking water) the tow was perfect, I didn't really push it on the highway maybe up to 70 max, but kept it around 60-65. Smooth as could be, extremely stable, zero sway. After the weekend, I decided that I would empty the tanks when I got back to my RV storage. The grey water tank was at about 50%, black water tank 45% full upon the end of the weekend. Immediately once on the freeway, I noticed it started swaying at about 62-64 MPH and got worse the longer I stayed at that speed. It was actually a little concerning. Any suggestions? I was thinking about adding Airlifts to the Tundra, and also I want to upgrade the tires on the trailer to a 10ply or something similar to what I run on my truck. Aside from this, we love it! Seems to be built solid, and I agree with some of the other posts, the bed needs to be topped with memory foam or something similar. Oh, and the TV speakers were the worst I have seen on a TV, not really a black series issue but cheap RCA? Anyone else experience this? One more thing, I think I may add the "poop tube sewer hose mod", I like the idea of keeping that mounted under the rig and out of the way. Look forward to more posts in the future.