There is a shared Sonar folder on everyone's system.
If you remove X2, you might well remove something that you'll regret deleting further down the line.
It's a really good idea to
not delete older systems - they don't consume much space.
And you cannot control what gets removed, although you can re-install just the bits you want by performing an advance install and just select those modules that are gone. But it's not 100% foolproof, so it's your choice.
V-Vocal has been superseded by Melodyne, not sure about R-Mix, but if you have X2 installed on your system, they should be available in X3
Another reason not to remove X2