Since I added a topper I noticed when I loaded the bed of the Tacoma the rear end was squatting pretty good, my neighbor showed me a box that had a set of 1250 lb load control springs that slide over the rear shocks made by superior , I went to pep boys and bought a set for 35 dollars, took about 30 minutes to install, and what a difference they made, I regained my height I had before the topper and the truck drives so much smoother and it took out the sway I had when cornering, it says the springs are self adjusting to the load and road conditions with a air ride quality best 35 bucks I've spent in along time