[Lynne]

You can remove this from the if statement:
AND $this->thread['forumid'] == $this->registry->options['vbcmsforumid']

Unfortunately, there isn't any flag in the thread table to say the thread is an articles comment thread. I suppose you may be able to look at the thread title and see if it has the word"Article:" at the beginning and use that in the if statement so the query isn't run for every thread.