Using kdiff3 to compare two different revisions of a folder

Hi, all!

    I would like to use kdiff3 to compare some folder like "include"
between two different revisions.
    It would be something like "git diff v2.5:makefile HEAD:makefile",
but for an entire folder.

    Kdiff3 give me a quick glance of its nice graphical output of the
differences, without have to resort to looking/parsing 'git log'
output.
    For now, easiest way for me is to keep my tree replicated in two
different folders pointing to different revisions then use it.

    Is there a better way to do this kind of comparison?

Thanks in advance,