If you hate installing all your Firefox extensions, plugins and custom tweaks when you do a fresh system installation, Silence of the Foxes will build you a custom and silent Firefox installation.
Silence of the Foxes works on both Firefox and Thunderbird, although most users will find it most helpful for streamlining Firefox installations.
Download Silence of the Foxes, extract the files, and run the main executable. You'll need a Firefox installation file for Silence of the Foxes to unpack and repack. During the second step you'll tell it what you want to include in the repack like your search plugins and bookmarks.
The default method is to pull from the existing Firefox installation—which makes it a great way to back up your present installation as-in—but you can jump into the .INI file and change where Silence of the Foxes looks for the Firefox installation and other settings.
Although it was originally designed for earlier versions of Firefox, the structure of directories and locations of key files has remained static and Silence of the Foxes still does a great job repacking all your favourite settings in a silent installation. Although we didn't have any issues with Silence of the Foxes, we can't emphasise enough the importance of backing up your Firefox profile before tinkering with Silence of the Foxes. We recommend previously reviewed MozBackup as a quick and easy way to backup your bookmarks, extensions, saved passwords and more. Silence of the Foxes is freeware, Windows only.