I've got the Truxxx lift (full kit) and also added Supersprings in the back.
I also have BFG TA/KO 305/65R18 All Terrain tires.
My trailer is on the smaller/lighter side at 21' and 5000 lbs loaded.
If anything, the truck feels better than stock while towing. Most of that can be attributed to the tires and a little to the Supersprings. Truck and trailer feel much more stable heading down the highway and climbing/descending twisty mountain roads. I get 8 to 12 mpg towing depending on terrain.
Stock height with better tires? Dunno, haven't done it. But mine definitely feels better towing now than it did stock.
