I don't have any experience with upgrades so before I purchase I would like to know how this will affect the site I'm currently using/making .
When I saw some of the upgrade information it seems very interesting but I have spend so much time on making my site that I don't really want to redo everything...

The main advantage would be the faster site and more fonts.
I'm not sure how the adaptability to various screen size would affect the look of my site.

If I download the trial version will I be able to look at the live preview without it affecting the site as is..as long as I don't "save" anything I'm assuming it would work ...