I'd look at regmon and filemon and set the filters to avoid getting everything that happens logged... But that is because I know of no better/more specialized tool for this.

Filemon probably won't directly tell you changes made to files (unless you dig through the exact content of all calls) but if you can make multiple installs, you can first locate which files that are touched, then in a second run document the files before/after installation. Regmon should tell you what gets added/modified...

/Michael