I have a popular website that gets about 2,000 uniques per day. The site is pretty much my bread and butter at the moment and it brings in quite a bit per year. This can most be attributed to the large user base and good search engine rankings. Up until now the site has been completely hand coded and managed. I have not used any CMS to streamline the site. It does have some wordpress blogs attached but all in all the site is not CMS based. I am considering moving it to a CMS system so I can streamline everything and make my life easier. I was wondering what are the SEO implications (especially serps). If I suddenly change from what I have now to a CMS. I will be using modx and the sites structure will remain mostly the same. So if I had a link www.mysite.com/page1.php the url's will remain the same. So could I lose rankings or should I just switch? I wouldn't really care normally but like I said this site is my bread and butter any large slip in serps could take a lot of money out of my pocket.