You may wish to run the installer with the --extract only option and take a look at Makefile. I believe this may answer all your questions.
Speaking of the Makefile, I just noticed it deletes all the old conflicting files before compiling the new ones. I think it might be a good idea to compile the new modules first, store them in a temporary location, and remove / replace the old ones after all the new modules are successfully built.
"Floating in a dream-like state, I am the emporer of a parallel universe." --Arch Enemy
My xorg.conf file