The results are in.
We just came back from a trip to Utah from Saskatchewan.
I had installed an EZ Flex kit and the shock kit.
I can't tell if the EZ Flex made any difference, the kit is supposed to lessen the jarring from small impacts, but I put them on for the durability factor anyway.
The shock kit however was most impressive! (I mounted them leaning out, as vertical as the kit allowed) Previously when hitting a large bump I would experience 3-5 after shocks in the truck as the springs oscillated. After the kit, all that was felt was the first bump....that's it! It isn't a perfectly smooth ride, but vastly improved. The steering is easier to control, the ride is more relaxing(it doesn't feel like a big dog is shaking the truck after every bump), the cupboard and fridge contents in our rear kitchen aren't moved around as much.
THIS WAS A GREAT MOD!!! And not that hard to do. I would say if you can change a tire and do an oil change you can do this mod.