I know there are many, many, many heavy dodge trucks out there running around on 6" lifts. Mine was also until I just couldn't stand the horrific ride quality, steering issues, and DW. But it did look good, and was cheap to add, relatively speaking. Most 6" lift kits do not adequately address the needed geometry change requirements in the front steering and suspension, as mentioned below with the comment about the control arm length, only to name one. I am not dogging BDS, Procomp, Skyjacker, and the others who do make some good lift systems for IFS 1/2 ton trucks etc. I just don't think they have what it takes to properly suspend our big 3/4 and 1 ton solid front axle rigs.
I am not going to try to sell you on a full blown $12K Carli, Thuren, or Kore suspension system, there are are other threads that can do that better than I could in one post. Nor do I want to hijack your thread and turn it into yet another Carli/Thuren/Kore thread. I only want to say that there are some of us out there that went with a run of the mill 6" lift kit, for the looks and the tire clearance, and the result was a disaster.
I pick mine up from R&R Offroad tomorrow with a complete Carli/King/Deaver/PSE suspension rebuild front and rear. I will have a used 6" BDS lift kit for sale, including dual steering stabilizer, factory rear leaf springs, and many other factory suspension components as soon as I get it all home in the back of my properly, bullet proof, suspended truck.