First let just say that your theme is incredible. I absolutely love it!
Now I did a search and could not find an answer to my question, but if by chance I missed the answer elsewhere, I apologize in advance.
I need to know if it is possible to only upgrade certain files. I ask this due to the fact that I have used an incredible amount of graphics and customizations for my site's appearance and I have had to re-due it several times after upgrading.