Purchased Firestone Airbags from SDTruckSprings. $321 with free shipping. Easy install except cutting off the rubber snubber, after that piece of cake, even on your back. Model: 2407 for my 2015 TRD Off Road Crew Cab. I pull a travel trailer and they work great.
I have learned that airbags (this type) are not for off road. Not much articulation allowed, and the bags will pull apart. But for the street or open highway they're great.