My question was probably not specific enough - sorry.
Example:
Today our top menu could be: "Automobiles" (which is the keyword, that we want to target) But "Cars" is shorter and easier to use, and looks better. There we would like to change it.
Below this we have several pages with: Automobiles in
How much value does it have to have the exact keyword in the main menu of the site?
- the menu is on all pages on our site.
We have several other internal links with anchortext "Automobiles" linking to the page.