There are two files you'll have to gander at, scripts/showprofile.php and templates/default/showprofile.tpl
The "outward appearance" is the tpl file, the "inner workings" is the script file which would include any sql queries.
As for increasing posts, that'd likely be done on one of the posts scripts (not sure offhand as I don't have an install available to poke at as i'm about ready to head out the door)
