Nice modification.
I have been thinking about it waiting for money for new truck, but spending 70 grands on new truck only to put additional $5k (with labor) to make ride bearable really sucks.
Commercial air bags have very long life span. I bought my Prevost when it was 32 years old and it was sitting for about a decade. I replaced 2 of the bags as they show outside abrasion from road debris, but sold the Prevost with several bags that had to be at least 25 years old, if not 40 years old.