A set of air bags most definitely will help. I have Firestones on my dually. Didn't think I needed them until after I got them
Best mod you can do to a tow vehicle. I also have a Viair onboard air system so I can adjust on the fly. Either brand, Firestone or Airlift will do fine. I just got the Firestones on sale with free shipping from Jeg's. Very nice addition to the truck!
2012 Sandpiper 365SAQ weighing @ 15k, Onan, 2nd air, slide toppers, TST
2013 F350 6.7L Lariat 4x4 CC DRW,Viair 1007, Ride-Rites, Edge CTS, B&W
2001 Chevy 3500CC DRW 4x4, 8.1L, 4.10 gears w/ Detroit TrueTrac
2001 Ford Excursion Limited 4x4 7.3L,V/B Spring Mod, ProComps, Hellwig Swaybar, & other 'Necessities'