404. That’s an error.
The requested URL /bookmarks/mark?op=edit&output=popup&bkmk=http%3A%2F%2Fwww.caraudio.com%2Fforums%2Fsubwoofers%2F569963-sub-will-loudest.html&title=which+sub+will+be+the+loudest%3F
was not found on this server. That’s all we know.