You might not need to replace those bushings yet, give it an inspection like Eurodat recommended...
If the noise (clunking) is coming during a start, chances are its the diff strap, its ment to catch the diff as it moves upward due to the torque applied to the diff.
There are other options for the diff strap.
1. replace the worn out rubber with something like a nylon tiedown strap
2. DIY your own RT style mount, you'll need some scrap steel, a drill, a disk cutter, and access to a welder, the bushing is generic. Make sure to leave a gap for the fuel lines.
Personally I would consider #2 if you have access to the tools. 2/3 times I've had clunking its been the front diff mount/strap, the other time it was the damn gland nut on the strut tube.