
BANS allows this and as long as you ALWAYS back up the files that you will be working with, you should be fine. I have added several mods to my website and most have dealt with making the site more search engine friendly. An interesting point about BANS is that you are working with php files as opposed to html. These type of files are server side applications and the necessary html for all of your web pages are actually created at your website hosting location when they are needed and are not available to you in the standard ways. But it certainly does make the amount of files that you have to work with be very small in number indeed.
This leads in to a point I want to make if you are thinking of building a website to make money. You absolutely must be able to make basic changes to your code if and when you ever need to customize your site. It really is not that difficult and you simply can't be waiting around for someone else to make what turn out to be very simple changes. Don't be afraid to make some mistakes. As long as you always remember to back up the files you will be fine.