So, i want to do a big change to my site... it's in html fully except the blog (which is wordpress). It's also not dynamic, as a result, and changing one little thing in the menu (header) or footer means i have to go through every page and change it manually. Although i know that the homepage will not be affected since its still just .com, all of the other pages which are in google's and bing's databases as .html will not exist, or at least not exist to the clients (if i keep the pages). i want to change the whole thing to php since i can use a universal header and footer and make my life a million times easier. what should i do? how will this affect my rankings for inner pages and the PR for those pages? can i do a redirect from the html pages to the php pages? i would love some advice with this... thanks!