I'm updating to Windows 8.1 and want to have everything from previous Sonars. I've upgraded yearly but I don't want to install all those versions, just the plugins that are no longer in X3 (like "R-Mix"). Who's done this type of thing and what can I expect?

One of the early screens presented by the SONAR install process has the Basic and Advanced options. Select the Advanced install option, a later screen will present all the individual options to install. The only plug-ins not separately installable are the ProChannel modules and V-Vocal. The ProChannel modules and V-Vocal require a minimum install of SONAR (the first check box on the advanced install component screen).

Because you'll need to do the actual program install to get VVocal make sure that you do the install starting with the oldest Sonar version first finishing with all of X3.

Do this because each installation of the plugins overwrites existing ones. You want to finish up with the latest versions of any installed plugins.

Just install original X3 files then X3d as it's a rolliup of all the updates.

scook
One of the early screens presented by the SONAR install process has the Basic and Advanced options. Select the Advanced install option, a later screen will present all the individual options to install. The only plug-ins not separately installable are the ProChannel modules and V-Vocal. The ProChannel modules and V-Vocal require a minimum install of SONAR (the first check box on the advanced install component screen).

I tried doing it this way (and I am, by far, not a computer novice) but doing things this way never got me to a screen where I could select individual plugins and totally screwed up my X1d Expanded installation. Not your fault, scook (naturally) so I'm not hammering on you, Cakewalk or anyone else. Just throwing out a note of caution to the OP. I'm not sure what I screwed up or if I screwed up while doing this, but I ended up reinstalling X1d-X (as well as 8.53 Studio) from scratch just to get all my plugins. I contemplated reinstalling Sonar 4 LE and Cubase xx-whatever to get those plugins, too, but decided I had to draw a line somewhere.
 
Bottom line: I have three versions of Sonar installed along with every plugin that came with them. And most of them I don't use anyway.