Just another opinion, having just done it recently, changing the rear shackles is no worse than changing the rear shocks. Its a matter of watching how much the spring moves and using common sense.
The "silent block" is another matter. Since you will have the rear shackles off, chase the u-bolt threads and remove the lower shock nut and washer and the four u-bolt nuts. Support the axle at the center and remove the front spring bolt. When the spring is out, you will have to destroy the old silent block to get it out. You can use and old socket and push the center bushing out. Then pull out all the old rubber. You can use a hacksaw or a power saber saw to cut a slot in the outer metal of the bushing. Once you have split the metal you can use anything to collapse it inwards and pull it out. Clean the rust out of the spring eye and push the new busing in with a vise or a large clamp using sockets as a pusher and receiver. Its really quite simple hammer and tongs work, but much easier with the spring off the car.
Remember, this is just another opinion on how I did it. Wear safety glasses and good gloves. Turn the radio up so the neighbors won't hear what you say.