As far as I know, nothing will change. But there may be problems with speed and plugins that call for files outside of WordPress if you do not limit the number of SSL enabled pages. I highly suggest installing a plugin and managing SSL that way.
SSL shouldn’t cause your site any problems. Our company just implemented a Symantec SSL and we didn’t experience any problems. I would suggest that you get an SSL manager plugin for the site that will restrict the pages that are loaded through an SSL to just payment an information pages. It will speed your site up considerably.
