How to Switch from one Update Site URL to Another

This guide applies to situations, when you want to stay on the same Eclipse Platform version, but you want to switch to another Dr. Garbage Update Site.
The following table shows some examples where such a switch makes sense:

From To
http://www.drgarbage.com/3.5/preview http://www.drgarbage.com/3.5/stable
http://www.drgarbage.com/3.4/stable http://www.drgarbage.com/3.4/sr1

To switch from one Update Site URL to another, please follow these steps.
Please note that the names of Eclipse GUI elements suit Eclipse 3.5 Galileo; the names may vary in other eclipse releases.

1. Uninstall all Dr. Garbage plugins

Help > Install New Software... > What is already installed?

Select all Dr. Garbage plugins and click Uninstall...

2. Remove all Dr. Garbage Update Site URLs

Help > Install New Software... > Available Software Sites

Select all *.drgarbage.com/* Update Sites and click Remove.

3. Restart Eclipse

4. Add new Update Site URL

Help > Install New Software... > Add...

5. Install plugins of your choice

See here for more Details: How to Download and Install Dr. Garbage Plugins