As you might know .MVC3 brings an alternative view engine named Razor.
As I understand in order to make this possible MS has put more effort in making integration of alternative view engines easier.
Will this have any impact for other view engines (nHaml, Spark ...)?
What I'm mostly interested in is tooling integration (syntax highlighting, code completion
etc).
That has nothing to do with MVC. It's related to writing Visual Studio plugins that recognize the file extension being opened and add syntax highlighting and Intellisense. So MVC 3 won't bring anything new in terms of tooling support for third party view engines (other than of course the syntax highlighting and the Intellisense for the Razor view engine built by Microsoft).