They are the best for the money and they have good flex to them, but I always try to go with BDS or a Zone kit where I can. They have a 2" spring but on the diesel trucks its more of a leveling spring, you can always add a block or add-a-leaf to the rear. The main reason I run bds is cause of their no BS warranty, if you break any part of the kit, they will replace it for free, forever!! No matter what. I also noticed, their springs can take a beating and less likely to sag over time and if they do, they will give you new springs.