I installed Timbrens based on the advice of another TDS member and could not be happier. My truck always has about 1500 pounds in the bed and used to squat. With the Timbrens the squat is gone and the ride is great. The Timbrens are only in play when the truck is loaded and require zero maintenance/adjustment. They take about a half hour to install and are relatively inexpensive. They don't seem to be too popular on this forum but I sure like them.
Timbren web site
Timbren web site