Keep in mind that sidebars also duplicate some of the calls made in ubbthreads.php - such as "newest user" and "who's online". By having the sidebar on your main index page, you are basically doing each of these queries twice - so I commented out the queries from the ubbthreads.php and then took out the Extra Information lines.
Probably the proper thing to do is check to see if a user has the sidebars turned off; but thats something for another day.