I had the same issue, I have a 2018 with around 50K miles and the rear was sagging so bad.... you set a cup of coffee on the tailgate and you have a Carolina squatted Raptor....... I HATED the nose high look.
I have about 3k miles on the Icon's (at the lowest setting) and the rear sits slightly higher than the front, and I have the Icon collars at max height in the front too....
They have been great and was a noticeable improvement on the rear end feel. I will say I have noticed a little noise every now and then from them, but have not tried to spray them as other members have suggested.
Here is a pic: Icon front collars - max, Icon rear leaf springs - lowest setting, 37 KM3s
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