They are NOT as simple as you think! I am a DIY'e and I did the diff mounts myself. It was a BEAR of a job. I did buy the tool neccessary to change them (around $100) and a few people on this site has made their own but, it is time consuming. Specially for a first timer. BTW, there is a picture of the tool, in the performance catalog. Don't even think of doing this job without this tool or your self made tool because the bushings will not come out, I promise you! Get a quote for the installation from your mechanic and then go from there.
Do a search o the topic.