One unique legal aspect: Image-Line has a regarding previous piracy. They famously stated they would rather people use a cracked version than not use FL Studio at all. However, they offer a massive discount for users who later buy legitimately. If you have a "repack" installed, uninstall it, buy the official version, and you can often open your old pirated projects.
: Using pirated software is a violation of copyright law and can lead to civil or criminal sanctions ( Image-Line ). The Official Alternative