Is there a downside of modifying the codes in the Smart Slider's files?
If you modify the codes in our files, those changes will be lost with the updating of the slider, and because new WordPress/Joomla/Magento versions, PHP versions will come out, the sources of the dynamic sliders will change their codes, our codes used today won’t work after a while, and you will need an updated Smart Slider. The best you can do is if possible make the changes in new files created by you, and call them in from your theme/template. It is much easier to give that extra css file incalling into the head, then to rewrite the whole code. If your changes has to be in our files, then keep in mind, that extensions/plugins were made to satisfy most people, which isn’t good if you want something really customized, and you should compromise, there are hundreds of possibilities, what you can do with our slider. Think about it, that is it really important, or just for you, and if your client wants it, explain the downsides to him.