

The installs are separate and they can be installed and uninstalled independently with a few caveats - this is for VS2015, but the same points apply to VS2017 ( Source):

The answer is that there's no difference between this and other side-by-side installations, and many developers keep several versions installed like this, especially if you're evaluating a Preview build. I've flagged this as a possible duplicate, but I'm not sure if your question relates specifically to the Preview edition of Visual Studio, so I'll answer here as well and let a mod decide.
