That looks like Cybernetic's Subforum Management plug:
https://vborg.vbsupport.ru/showthread.php?t=201294
Either that, or it could be the one by Sorky. But, I think it's Cyb's that shows the the post numbers like that. Here is the latest version of the sorky plug:
https://vborg.vbsupport.ru/showthrea...12#post1727012
For the strikethrough on banned users, you can try <s> or <strike> in the html markup for the banned usergroup. Unless for some reason your doctype is xhtml strict (i believe it should be xhtml transitional),in which case you might need to use <del>. Just put the opening tag in the first box and the closing tag in the second.
For highlighting you can just set a background color in that same usergroup markup box.
Example:
opening box:
Code:
<strike><span style="background-color:#000000; color: #ffffff;">
closing box:
Insert your own colors and additional markup that you want, obviously.