Couple of changes you may want to make to get it to work with these changes. You'll want to remove
.Community .header_body {
background: -moz-linear-gradient(center top , #1b1b1b 0%, #141414 100%) repeat scroll 0 0 transparent ! important;
background: -webkit-gradient(linear, left top, left bottom, from(#1b1b1b), to(#141414)) repeat scroll 0 0 transparent ! important;
}
in order for the forum banners to show up. You'll also want to remove
border-left: 1px solid #212121 !important; from .column.main near the top.
I'd also suggest adding
.muted {display: none ! important;}
.header_body_page h1 a {display: none ! important;}
.header_body_page h1 a:hover {display: none ! important;}
body.loaded footer {display: none ! important;}
.container_out {border: none ! important;}
.header_body_page {height: 0px ! important;}
In order to get rid of that stuff near the top and bottom as well as hidden posts. And adding
.forumPost .header_post {border-left: none ! important;}
.forumPost .header_post {background: -moz-linear-gradient(left, #141414 19%, #2d2d2d 100%) !important;}
to fix the thread titles section.