Checkout the Timbren SES suspension assist. I just installed these in lieu of airbags based on feedback from those that have them here. Came recommended by Slee and installed in 20 minutes. Biggest issue is figuring out the spacers you need for the amount of droop you have.
I'm running mine with a 1" and 1/2" spacer and Slee Heavy Springs (running drawers and an RTT). Here's a picture of the sag I had before I installed them.
View attachment 897237
Now I ride level!