Good question - the reasons for the lift are:
1, to lose the AHC. I'm sure I don't need to go too far into this, seems to be a pretty common opinion here.
I have a truck with AHC and one with a full OME kit on it with the diff drop. I won't be pulling the AHC off my other truck until it has some sort of catastrophic failure. Unless you are carrying LOTS of weight, the AHC is probably just fine. Failure rates are not as frequent as people would have you believe.
Take the path of least resistance for a while. Put on new tires and get used to the truck, drive it for a year and see what you really need. Learn about your truck. Call Christo and get him to help you decide. I did, and am very happy with my OME truck.