Again, I have 8.5 X1 and X2 on both systems.
You need 3 drives on your system.
C: OS, Sonar, all vst dll's
D: Audio, this is where all your projects reside
E: Samples
for example; this is where the dimpro content resides
Leave X1 on your system, its just easier...
HTH,
T

Thanks - I'll leave X1 on there - though my question is that Beatscape and DimPro are installed in my VST plugins folder which I imagine would be common to X2.  So how do I avoid Beatscape and DimPro from X1 conflicting with X2 if they are installed in the same common VSt plugins folder?  Sorry for being dense here.  And yes, I have a C, D, & E like that - only C has Cakewalk & my VST plugins (separated out into 32bit & 64bit folders) and my E has folders for the samples & content (including the Cakewalk specific stuff).
 
I do appreciate the help from both of you and your patience with my setup noobyness. :)
 
And one last thing, if you don't mind, is there still any issue with 32bit vs 64bit VST plugin compatibility?  Will I be able to run a 64bit X2 and use all my plugins regardless if they are 32bit (like some of my IK plugins) or 64bit?  thx!

The Beatscape synth was dropped from X2, the REX files were migrated to the Loops and One Shots library. Unless you actually use the Beatscape synth, uninstall it. The installer is separate from X1. If you do use Beatscape, delete the library and create a junction to the Audio Loops.
 
DimPro is a separate installer and there is no reason to install it if you have installed it with X1. The DimPro versions are completely identical, forget the X2 DimPro install. FWIW, you cannot have more than one 32bit and one 64bit install of the DimPro anyway due to the registry entries.
 
There will always be some issues with 32bit plug-ins in a 64bit environment. The best thing to do is either avoid 32bit plug-ins all togther or run them in the 32bit version of the host. The bridge technology from Cakewalk is the same in X2 as it was in X1.

thank you for that info.  That was mostly what I was after to find out.  If I recall correctly, all these old 32bit IK plugins like SampleTank (which I'm pretty sure IK didn't make 64bit yet) did work in X1 64bit so I guess that same bride technology should work for me in X2.
 
Also thanks for the info on Beatscape & DimPro... :)