You will love the onboard air system! I believe it is the best mod you can do to a TV(in conjunction with bags). I run around 12 PSI in my bags when empty. When loaded, it goes up to around 34 PSI. I love being able to adjust on the fly. When the interstates get bumpy, I usually go up to around 40-45 psi to help with the bouncing of the roadway. Here is a pic of my Viair system installed.
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'