That kind of makes me laugh...."I think the best way to help me would be to just give me the code for what I want to do". Anyway, you had half the code.
Code:
<if condition="$vbulletin->userinfo['userid'] == 14">
<span id="repdisplay_$post[postid]_$post[userid]"><b>Reputation:</b> ∞</span>
<else />
<span id="repdisplay_$post[postid]_$post[userid]"><b>Reputation:</b> $post[reputation]</span>
</if>