Changing background color in vim at a certain column

Answer 1

Try this:

:match ErrorMsg '\%>80v.\+'

It will highlight text beyond 80 characters, you can replace '80' with whatever wrap-width you have. However, it will only highlight the characters that exceed the width, and then only on lines that are actually longer than the width.

Check http://vim.wikia.com/wiki/Highlight_long_lines for more info, but they all pretty much accomplish the same thing.