Putting lift keys on will have the same effect as the stock keys (or worse) because the "lift keys" will be turning the torsion bars just like the stock keys but just have a greater range of motion. A lot of people on this site say that the stock keys will lift the truck all the way to the bump stops making the lift keys useless. I Put lift keys on mine and it did lift the front end farther than the stock keys. This could be that my torsion bars are warn to the point that they do not have as much spring in them anymore. Also, My ride is extremely rough with the keys turned up far enough to run my 305/70/16s on my 16x10 wheels.
My personal opinion would be to wait and get a 4-6 inch lift and crank it to 5"
Hope this helps