めも

先ず、サイドメニューを狭くします。今回は120pxだけ狭くします。あとでその分コンテンツ幅を広げます。
サイド領域(div#BodyBlockSide)
font-size:10px;
line-break:strict;
word-break:break-all;
サイドメニュー領域(div.SideMenu)
width:180px;
float:right;
何シテル？ヘッダー(div#NanisiteruHeader)
width:170px;
何シテル？領域(div#Nanisiteru)
width:160px;
何シテル？フッター(div#NanisiteruFooter)
width:170px;
font-sizeは好みで替えてください。

タブの上部マージンを多くします。これをしないと広告とコンテンツが重なってしまいます。
タブ(ul#MainNav)
margin:228px 0 8px 0;

ヘッダーと広告を重ねて表示する場合の必須になります。
ユーザー領域(div#MinkaraBody)から
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/back.gif);
background-repeat:repeat-y;
background-position:center;
background-attachment:fixed;
background-color:#444;
をページBody(body)へ移動

広告と重ねるので偽ヘッダーの設定。
オリジナルで作る場合、幅を狭くしても良いでしょう。
ヘッダー領域(div#BodyBlockHeader)から
background-image:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/header.gif);
をユーザー領域(div#MinkaraBody)へ移動

background-repeat:no-repeat;
background-position:50% 8px;
をユーザー領域(div#MinkaraBody)へ追加

ヘッダー領域(div#BodyBlockHeader)ヘッダサイズによりお好みで
height:50px;

今までの物は準備でコレがメインです。とりあえず120pxだけ広くしていますが、marginやpadding、サイドメニュー幅をギリギリまで調節すると、800pxにも出来ます。
コンテンツ領域(div#BodyBlockMain)
overflow:visible;
コンテンツ表示(div.contents)
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/contents.png) repeat-y;
を削除
background-image:url(http://carview-img02.bmcdn.jp/carlife/images/UserCarNote/750640/p3.jpg);
width:700px;
を追加
コンテンツ表示上部(div.contentsHeader)
コンテンツ表示下部(div.contentsFooter)
共に
width:740px;
background:url(***)*** no-repeat;をrepeat-xに修正

コメント幅の調整
コメントタイトル(table#userCommentList td div.commentTitle)
コメント日付(table#userCommentList td div.commentDate)
コメント表示(table#userCommentList td div.commentArea)
共に
width:310px;

/*--------------------------------------
User Custom CSS
UserID = 240136
Date = 2009/10/30 21:40:25
--------------------------------------*/
body{
margin:0;
padding:0;
font-size:14px;
line-height:1.6;
color:#222;
font-family:'ＭＳ Ｐゴシック',Hiragino Kaku Gothic Pro,sans-serif;
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/back.gif);
background-repeat:repeat-y;
background-position:center;
background-attachment:fixed;
background-color:#444;
}
div#BodyBlockMain{
float:right;
overflow:visible;
display:block;
width:620px;
}
div#BodyBlockSide{
float:left;
overflow:hidden;
display:block;
clear:none;
font-size:10px;
line-break:strict;
word-break:break-all;
margin-top:10px;
width:300px;
}
a{
color:#00b7ec;
text-decoration:none;
}
a:hover{
color:#00b7ec;
text-decoration:none;
}
a:visited{
color:#00b7ec;
text-decoration:none;
}
a:active{
color:#00b7ec;
text-decoration:none;
}
div#MinkaraHeader{
background-color:#444;
}
div#MinkaraBody{
clear:both;
overflow:hidden;
font-size:13px;
line-height:22px;
display:block;
background-image:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/header.gif);
background-repeat:no-repeat;
background-position:50% 8px;
margin:0;
padding-top:0;
padding-bottom:20px;
padding-left:0;
padding-right:0;
width:100%;
}
div#BodyBlock{
color:#fff;
margin:0 auto;
padding:0;
width:930px;
}
div#BodyBlock a{
color:#00b7ec;
text-decoration:none;
}
div#BodyBlock a:visited{
color:#00b7ec;
text-decoration:none;
}
div#BodyBlock a:hover{
color:#00b7ec;
text-decoration:underline;
}
div#BodyBlock a:active{
color:#00b7ec;
text-decoration:underline;
}
div#BodyBlockHeader{
height:50px;
float:left;
overflow:hidden;
display:block;
width:930px;
padding:0;
margin-top:5px;
margin-bottom:0;
margin-left:0;
margin-right:0;
}
div#BodyBlockHeader h2{
font-size:24px;
margin:16px 67% 0 17%;
padding:0;
line-height:1;
height:24px;
background-color:transparent;
}
div#BodyBlockHeader h2 a{
color:#fff;
background-color:black;
}
div#BodyBlockHeader h2 a:visited{
color:#fff;
background-color:black;
}
div#BodyBlockHeader h2 a:hover{
color:#fff;
text-decoration:none;
}
div#BodyBlockHeader h2 a:active{
color:#fff;
text-decoration:none;
}
div.paging{
text-align:center;
clear:both;
}
div#BodyBlockMain div.paging a{
margin-right:10px;
}
div#BodyBlock div.paging a.thisPage{
color:#333;
font-weight:bold;
}
div#BodyBlock div.paging a.thisPage:visited{
color:#333;
font-weight:bold;
}
div#BodyBlock div.paging a.thisPage:hover{
color:#333;
font-weight:bold;
}
div#BodyBlock div.paging a.thisPage:active{
color:#333;
font-weight:bold;
}
div.userTag{
margin:0 0 10px 20px;
font-size:12px;
}
div#BodyBlockMain div.userTag a{
margin-right:5px;
}
div.userTagRelationDoc{
margin-top:10px;
display:none;
}
div.userTagRelationDoc ul{
padding:0px;
margin-top:10px;
}
div.relationLink{
font-size:12px;
padding:5px 1.5em;
margin-bottom:5px;
}
div.contents{
margin-left:-120px;
padding:0px 20px 8px 20px;
width:700px;
background-image:url(http://carview-img02.bmcdn.jp/carlife/images/UserCarNote/750640/p3.jpg);
}
div.contentsFooter{
margin:0 0 10px -120px;
padding:0px;
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/contentsFooter.png) top left repeat-x;
height:4px;
width:740px;
}
div.contentsSubTitle{
margin:5px 0;
padding:3px 0;
clear:both;
text-align:right;
font-size:12px;
}
div.contentsTitle{
padding:10px 0px 15px 40px;
font-size:14px;
font-weight:bold;
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/icon1.gif);
background-repeat:no-repeat;
}
div.contentsHeader{
margin-left:-120px;
padding:0px;
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/contentsHeader.png) bottom left repeat-x;
height:4px;
width:740px;
clear:both;
}
div.contentsImpression{
float:left;
width:45%;
padding-left:20px;
text-align:left;
}
div.contentsEditDate{
float:right;
width:45%;
text-align:right;
}
div#BodyBlockMain div.blogEntryDate{
font-size:11px;
letter-spacing:1px;
text-align:right;
color:#888;
padding-top:10px;
margin-bottom:-20px;
}
div.blogMemo{
line-height:1.4;
font-size:14px;
background:;
}
div.blogMemo img{
padding:5px 10px 10px 0;
}
div#BodyBlockMain div.blogPosted{
clear:both;
text-align:right;
border-bottom:dotted 1px #444;
margin-top:2em;
padding-top:10px;
font-size:11px;
width:100%;
}
div#BlogChgView{
font-size:11px;
color:#444;
text-align:right;
clear:both;
margin:0 0 5px 0;
padding-right:5px;
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/e_bg.gif);
background-position:right top;
background-repeat:no-repeat;
}
div#BlogChgView a{
font-size:11px;
}
div.trackBackURL{
margin-left:20px;
}
#BodyBlockMain div.contents div.blogMemo .pho .pup{
position:fixed;
top:6%;
right:6%;
background-image:url('http://carview-img02.bmcdn.jp/carlife/images/UserCarNote/750640/p6.jpg');
padding:10px;
-moz-box-shadow:5px 5px 5px gray;
-webkit-box-shadow:5px 5px 5px gray;
opacity:0;
display:none;
}
#BodyBlockMain div.contents div.blogMemo .pho:hover .pup{
opacity:1;
display:block;
}
div.userCarListEntryDate{
text-align:right;
border-top:dotted 1px #006f9d;
clear:both;
width:100%;
padding:5px;
font-size:12px;
}
div.userCarListMemo{
float:right;
width:69%;
}
div.userCarListPhoto{
float:left;
width:30%;
overflow:hidden;
height:150px;
}
div.userCarListTitle{
font-size:16px;
font-weight:bold;
padding:10px 20px 10px 0;
}
div.contents h3{
padding:15px 20px 0 0;
margin:0px;
}
div#UserCarNav{
text-align:center;
margin:10px 0;
padding:5px 10px;
font-size:12px;
}
div.userCarPhotoMemo{
margin-bottom:1.5em;
}
div#UserCarPhoto{
text-align:center;
}
table#UserCarProfile{
width:100%;
border-collapse:collapse;
font-size:12px;
margin-bottom:1.5em;
}
table#UserCarProfile th{
width:6em;
text-align:right;
padding:5px 10px;
border-bottom:dotted 1px #444;
}
table#UserCarProfile td{
padding:5px 10px;
border-bottom:dotted 1px #444;
}
table#UserCarPartsCategory{
width:95%;
margin:10px 20px;
}
table#UserCarPartsCategory td{
width:50%;
vertical-align:top;
}
table#UserCarPartsCategory ul{
list-style:square;
margin:0 0 1em 0;
padding:0 0 0 1.5em;
color:#24a4e1;
}
table#GalleryList{
margin-bottom:1em;
}
table#GalleryList td{
vertical-align:top;
padding:0 0 10px 20px;
}
div.galleryTitle{
background:#0085cb;
color:#fff;
font-weight:bold;
margin-bottom:1em;
padding:3px 10px;
clear:both;
}
div.galleryPhoto{
width:50%;
overflow:hidden;
float:left;
margin:0 0 15px 0;
}
div.galleryMemo{
width:50%;
float:right;
margin:0 0 15px 0;
}
div.workDate{
text-align:right;
padding-top:5px;
margin-bottom:1em;
width:100%;
font-size:12px;
border-top:dotted 1px #006f9d;
}
span.star{
color:#fc0;
}
table#SpotList{
width:100%;
font-size:12px;
}
table#SpotList th{
margin:0px;
padding:6px 3px;
text-align:left;
border-bottom:dotted 1px #444;
}
table#SpotList td{
padding:6px 3px;
border-bottom:dotted 1px #444;
}
div#SpotPhoto{
text-align:center;
}
div.spotPhotoMemo{
margin-bottom:1em;
}
div.threadAction{
border-top:solid 1px #006f9d;
margin-top:10px;
padding:5px;
background-image:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/1bg.png);
}
div#BBSIntroduction{
font-size:12px;
margin:10px 0;
padding:10px;
border:solid 1px #999;
}
div.threadMemo{
border:solid 1px #006f9d;
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/1bg.png);
display:none;
margin:10px;
padding:8px;
}
div.bbsTop{
text-align:right;
font-size:12px;
margin-top:10px;
}
div.thread{
padding-bottom:10px;
line-height:1.75;
background-image:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/1bg.png);
}
div.threadTitle{
padding:3px 10px;
font-weight:bold;
}
table#BBSWrite{
margin-top:15px;
font-size:12px;
background-image:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/1bg.png);
width:100%;
}
table#BBSWrite th{
width:10em;
text-align:right;
padding-right:20px;
vertical-align:top;
}
table#BBSWrite td{
vertical-align:top;
}
table#BBSWrite td#BBSEntry{
text-align:center;
padding:5px 0px 5px 0px;
}
ul#MainNav{
width:100%;
list-style-type:none;
margin:228px 0 8px 0;
padding:0px;
clear:both;
height:30px;
float:left;
}
ul#MainNav li.nav{
font-size:12px;
width:19.5%;
height:30px;
float:left;
display:block;
text-align:center;
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/tab_bg2.gif);
background-position:center;
margin:0 2px 0 0;
line-height:2.5;
}
ul#MainNav li a{
color:#fff;
display:block;
height:30px;
}
ul#MainNav li.navOn{
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/tab_bg.gif);
background-position:center;
color:#fff;
}
ul#MainNav li.navEnd{
width:19.4%;
margin:0px;
}
table#userCommentList{
margin:0;
padding:0;
width:580px;
}
table#userCommentList td{
vertical-align:top;
border:solid 1px #006f9d;
width:50%;
}
table#userCommentList td div.commentArea{
width:310px;
margin:5px;
padding:5px;
font-size:12px;
line-height:1.65;
}
table#userCommentList td div.commentDate{
color:#888;
text-align:left;
width:310px;
padding-left:10px;
font-size:10px;
line-height:0.5;
font-family:Verdana;
}
table#userCommentList td div.commentTitle{
width:310px;
padding:8px 0 5px 10px;
font-weight:bold;
font-size:12px;
}
div#MoveCommentForm{
text-align:right;
margin:5px 20px;
}
div#HandleName{
margin:5px 10px 10px 0;
clear:both;
font-weight:bold;
font-size:14px;
}
div.profileCategoryTitle{
margin:10px;
font-weight:bold;
}
div#BodyBlockProfileMain{
overflow:hidden;
display:block;
margin-bottom:10px;
padding-bottom:10px;
float:right;
width:610px;
}
div#BodyBlockProfileSide{
color:#fff;
background-image:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/2bg.png);
display:block;
overflow:hidden;
margin-bottom:10px;
padding-bottom:10px;
float:left;
width:300px;
}
div#SelfIntroduction{
margin:0 20px;
font-size:12px;
line-height:1.3;
}
div.memberCount{
height:40px;
margin:10px;
text-align:center;
padding:10px 0 8px 0;
font-weight:bold;
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/f_bg.gif);
background-repeat:no-repeat;
-webkit-border-radius:5px;
-moz-border-radius:5px;
}
table.thumbnail div.thumbTitle{
width:50px;
text-align:left;
margin:5px auto 15px auto;
font-size:12px;
line-height:1.4;
}
div#SideFriendListAll{
text-align:right;
margin:10px 8px 0 0;
font-size:12px;
}
div#SideGroupListAll{
text-align:right;
margin:10px 8px 0 0;
font-size:12px;
}
div#SideRecommendedList{
text-align:right;
margin:10px 8px 0 0;
font-size:12px;
}
table.newDocument{
width:100%;
border-collapse:collapse;
color:#fff;
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/contents.png) repeat-y;
}
table.newDocument td{
font-size:12px;
padding:5px 10px;
}
table.newDocument td.entryDate{
width:110px;
text-align:right;
}
div.newDocumentAll{
text-align:right;
margin:5px 0 0 0;
padding-right:15px;
font-size:11px;
background:url(e_bg.gif);
background-position:right top;
background-repeat:no-repeat;
}
table#UserProfile{
width:99%;
border-collapse:collapse;
background-image:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/1bg.png);
margin-left:1px;
}
table#UserProfile th{
width:150px;
color:#fff;
vertical-align:middle;
padding:5px 0;
font-weight:normal;
font-size:12px;
border-bottom:dotted 1px #444;
}
table#UserProfile td{
vertical-align:top;
padding:5px 0 5px 10px;
font-size:12px;
border-bottom:dotted 1px #444;
color:#fff;
}
div#MinkaraEntryDate{
text-align:right;
font-size:11px;
margin-right:3px;
letter-spacing:0.1em;
color:#fff;
}
div.sideMenu{
width:180px;
float:left;
margin-left:-5px;
padding-bottom:10px;
background-image:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/2bg.png);
}
div.sideMenuContent{
margin:7px;
}
div.sideMenuTitle{
padding:3px 0 3px 0;
background:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/title_bg.gif);
background-repeat:no-repeat;
height:30px;
color:#00425a;
text-align:center;
letter-spacing:2px;
}
div#BodyBlockSide div.sideMenuTitle a{
color:#00425a;
text-decoration:underline;
}
table#Calendar{
width:105%;
text-align:center;
font-size:13px;
margin-left:-5px;
}
table#Calendar td.today{
background:#ffa500;
}
table#Calendar td.today a{
color:#333;
}
table#Calendar td.today a:visited{
color:#666;
}
table#Calendar td.today a:hover{
color:#fff;
}
table#Calendar td.today a:active{
color:#fff;
}
table#Calendar td.writingDate{
font-weight:bold;
}
div#Nanisiteru{
width:160px;
margin:0 auto;
padding:5px;
color:#fff;
}
div#NanisiteruHeader{
width:170px;
margin:0 auto;
height:16px;
}
div#NanisiteruFooter{
width:170px;
margin:0 auto;
height:5px;
}
div#Nanisiteru div{
text-align:right;
font-size:10px;
color:#fff;
margin:0px;
font-family:verdana,Tahoma,Sans-serif;
}
div#SideUserInfo{
margin:0.5em 0;
}
div#SideUserMemo{
margin-bottom:0.5em;
}
ul.userMakeList{
list-style-image:url(http://carview-img01.bmcdn.jp/cvmaterials/minkara/user/css/053/listicon.gif);
margin:0 0 1em 0;
padding:0 0 0 1.5em;
color:#000;
}
ul.userMakeList li{
margin-bottom:5px;
}
div.userMakeListTitle{
margin-bottom:0.5em;
font-weight:bold;
}