[deathemperor]

find in postbit template for $post[username] , then place it before the $post[date] or $post[time], for rank it's $post[rank], find this in postbit templte

<if condition="$post['rank']"><div class="smallfont">$post[rank]</div></if>

then place it under

<if condition="$show['avatar']"><td class="alt2"><a href="member.php?$session[sessionurl]u=$post[userid]"><img src="$avatarurl" alt="<phrase 1="$post[username]">$vbphrase[xs_avatar]</phrase>" border="0" /></a></td></if>

the rank will then be under the user's avatar.

for username size

<a class="bigusername" href="member.php?$session[sessionurl]u=$post[userid]">$post[musername]</a>

class="bigusername" mean the size's big, you can change it right there by either replace class="bigusername" with a "style" element or using the span/div/font tag.