Tortion bars
#3
Pros: you can even-out suspension that has sagged at different rates; you can add height, and ... ???
Cons: you can over-heighten them, causing an alignment issue not easily fixed; you could, I suppose, make the sides more uneven if you were a goof; you can approach a limit of your shock-absorbers' range so that they won't allow the a-arm to go down any more in repsonse to a hole/drop-off; and I guess you could make a truck less aerodynamic if the front end was too high compared to the rear.
Cons: you can over-heighten them, causing an alignment issue not easily fixed; you could, I suppose, make the sides more uneven if you were a goof; you can approach a limit of your shock-absorbers' range so that they won't allow the a-arm to go down any more in repsonse to a hole/drop-off; and I guess you could make a truck less aerodynamic if the front end was too high compared to the rear.