We offer a similar kit 57138
, which is a 5,000 kit for your application.
When it comes to air bags and WD hitches, there are various opinions I have seen. They most certainly have an effect on one another though. Many people will setup the WD hitch leaving it sag slightly and then bring it level with the bags. Others like to level the truck with the bags and then use the WD hitch one the trailer is loaded.
I would think your best route would be to hook up just as you normally would and then add air to the bags to bring it level. Many that level first with the air is because they have something heavy in the bed of their truck such as a 4 wheeler. It typically comes down to the owner just figuring out what rides the best for them during use. This is the easiest with a controller
so that you can adjust on the fly but can be also done with just a portable compressor and pulling over occasionally.
I would also suggest you contact the manufacturer of the WD system and get their recommendations. I'm sure they have fielded many a similar question.