I have a PR3 that has good rankings for a number of keywords, I want to make a few includes for my dropdown nav, footer, and scripts... do you guys think I would have any problems making this transition? I would hate to lose traffic or do something that would actually hurt my site in any way.
you will not lose any traffic or compromise your ranking for implementing SSI on your site. i'm assuming you already have the nav bar and footer on your site and instead of making them static, you want to implement SSI so that future update can be easy. as far as search engines go, they can't tell whether you are using SSI or not so it will not hurt your site any way.