I have about the same truck as the OP, except mine is a crew cab. My fifthwheel is a little heaver.
changes I have made:
Firestone air bags. I run them at 30 psi that levels the truck and keeps the lights on the road at night. Ride is better with them.
Glide ride pin box helped the ride. The trailer did not cause as much movement of the truck when on the road.
Bilstein shocks helped, but the old shocks were getting weak.
The truck had an Edge tuner on it when I got it, I would not have bought it other wise. I like it for the gauges. I use exhaust gas temp, gear, boost.
The biggest advantage of getting a tune would be to get an exhaust brake as part of that.
However there is a trick to get an exhaust brake on and LBZ with a switch. It works on most LBZs and cost only a few dollars for some pins, wire and switch. I just sad it did not work on mine.
