There should be an option to display post count under the user's avatar that also can display their rank. Sorry if this is already available but I haven't figured out how to do it yet.
If your referring to the .messageUserBlock .extraUserInfo then that is the default colour. You can (in the same area) if you were inclined to do so set the same background colour.
You can change the Message count title by going into the phrase manager and renaming it in there.