I know we talked over in the other thread, but towards the end of page 1 and top of page 2 of my build thread (linked in description) has the install of my front bags. I do think it makes a difference and was worth it, but it's a little easier for me since I was doing the rear and the control system anyway. If you are just doing the front keep in mind you really do need some sort of auto leveling valve and onboard air, bags do change height with temperature and sitting around. When I did the fronts on my 2003 3500 I never got around to plumbing in any sort of height control, I just ran a schrader valve to each bag and it was kind of annoying adjusting them every few weeks.
Two other things to consider - a significant portion of the cost for any of the Kelderman kits are the fancy Raptor shocks. They are very high end pieces and I think they run around $750 a pair. If they would let you order the kit minus shocks you could probably spend half that on some still very decent Bilsteins or whatever your preference is. Also Kelderman very occasionally runs 10% off and/or free shipping, and given that we're coming up on Black Friday I wouldn't be surprised if it's that time of year. I was able to take advantage of both when I bought my kits and that was a very significant savings.