Wondering if I should do a complete removal of my Sonar Producer 8.3 before trying to load up my new X3 Studio....     or can they both be on my computer at the same time without any glitches ?
 
V-Vocal doesn't appear to be in X3 Studio, maybe also some other features I'm not aware of, thinking I may need to go back to 8.3 to tweak things in my 8.3 recordings once in a while .... ?
 
Thanks much !

It would be best to leave 8.3 installed and add X3 Studio. After installing X3 Studio apply the X3e update then reset and rescan plug-ins.

Yup, Scook is right - leave it on there, won't do any harm and you'll keep all your plug-ins intact that are no longer included. Always handy to have the version that projects were created in available anyway. When reworking an older project in X3 the first thing I do is "save as" and add X3 to the project name and work on that version in X3, keeping the original project as was in case of any plug in compatablility issues.