Highlighting long lines in vim

I've become a bit obsessive about wrapping my lines to 80 columns, whether code or text. It's an aesthetic thing for me, mostly, but there are practical benefits. I autowrap comments in vim with formatoptions+=c and set textwidth=79, but I don't want to autowrap code because I sometimes I think it's appropriate to extend a few characters over, or the file might be a legacy file that where a formatting diff is unwelcome. So, for those times, I use the following lines in my vimrc to progressively highlight long lines: lines 80-90 characters in width are highlighted with a subtle shade of red, while lines longer than 90 characters are highlighted in a more noticable shade of red:

" Highlight lines longer than 80 characters as dark-red, lines longer than 90
" characters as a brighter red.
augroup vimrc_autocmds
    autocmd BufEnter * highlight OverLength ctermbg=124 guibg=#990000
    autocmd BufEnter * highlight SortaOverLength ctermbg=52 guibg=#330000
    autocmd BufEnter * match SortaOverLength /\m\%>80v.\%<91v/
    autocmd BufEnter * 2match OverLength /\m\%>90v.\%<140v/
augroup END

Two matches can be active at any one time in a vim document, so we match each portion of the line separately. Colors can be configured to your liking, obviously, and are currently set for terminals with a dark background and 256-color command-line vim. Additionally, it won't highlight past 140 characters to prevent slowdown with really, really long lines.