Excellent extension! Rated 5 out of 5 stars
First off, @bruceb: You can add any customized code. Tools > Options > Extensions > BBCodeXtra > Options > Custom tags then add them.
I do have a suggestion though. I would LOVE to be able to import/export settings. I use several computers and Firefox's browser sync doesn't sync settings. I could keep a copy of the settings in dropbox and quickly upload it to any computer.
Many thanks though! This has been one of my favorites for years. I cannot live without it.