My last three trucks have been chevy duramaxes. I have lifted all of them differently. First truck I only bagged in rear. Wasn't much clearance. The second truck I cranked torsion bars and and put bigger tires on it. This was an 05 and and 06. My last truck, which is an 08, I changed out the keys and increased tire size. Much better ride than cranking the keys!
I also air bagged the rear. My third choice was much better all around. Keys are only about 100 bucks, plus the airbags.
Well are you looking for ground clearence or suspension clearance, if you want ground clearance you have to do a suspension lift with bigger tires, if you want more clearance between the fenders say, and the tires do timberens or air bags, on the front you can raise by adjusting the torson bars or putting torson bar leveling clips in, but if you go to much you will explode the ball joints. Timberen does make overloads for the front. Of course if you do the overloads or airbags you might get enough more clearance for a bigger tire, to give you a little more ground clearance.