Dennis, If you plan to run a Air ride package you shouldn't need anything else! Depending on what air ride package you go with of course.
The Ridetech Level 3 info from their site = This is our performance system and it includes the best of every option we have to offer. If you are looking for the most versatile, and best performing system, then this is the option you should consider. Upgrades like StrongArms, MuscleBars, and the AirPOD control system are nearly always included in the Level 3 system. Includes: upper & lower tubular A arms, upper & lower rear control arms, Splined sway bar, etc.. $7,150
That is a complete suspension system so there would be no need for anything else.
Even the Level 2 comes with everything to upgrade your suspension and still no need for anything else.
I say choose one to go with and be done, If it were me and I had the money it would be Ride Tech (air ride) Hands down! I have been in several of cars equipped with their set up's and they are remarkable.
Scot W.