Fitting the body lift is quite an easy job, if you undo all the body to chassis bolts along one side and loosen the other side by a couple of turns it's quite possible to jack up the body along one side with a couple of trolley jacks and blocks of wood and fit the packers and bolts along that side. Then undo the bolts on the other side and lift the body on that side and then fit the bolts and packers. Most of the bolts are quite accesible ( like under the floor mats for example )the only ones I struggled with a bit were the bolts near the rear shock mounts , it's a bit fiddly to get the packers in. Obviously you need the bumpers off, (and they will need lifting or modifying too) but it's not too bad really, a couple of hours for the main body. I made my own kit up with 30mm nylon spacers. Things to watch out for are the brake and fuel pipes being stretched too much.
Note that you dont need longer shocks, you are lifting the body higher on the chassis, not modifying the suspension.
Steve the grease