As long as it is a low 3" lift then you can use rubber castor correction bushes. With a big 3" lift you would need drop boxes or radius arms.
You would need the upper adjustable trailing arms to tune out vibrations. I have heard of people getting rid of them with gearbox spacers but I would definitely bight the bullet and go straight to the adjustable upper arms.
If you were short on cash, you don't need the lower arms. Strength is the major reason for getting lowers. If for some reason you can't tune out the vibrations then a high pinion rear diff is the best solution.
If you had a long range tank fitted under the driver then you are likely to need a bent upper arm and adjustable lower arms. If you needed a bent upper arm, it might be good idea to fit a shorter bent upper arm and matching pair on the other side so you didn't have to adjust the diff too far back causing your tyres to hit your mud flaps when the tyre is compressed up into the guard.
Shane