Most likely a dumb question.....I just upgraded to X3. I show on my PC ATM sonar 8 studio, 8.5 producer, x1 producer & x2 producer.
 
Can I safely un-install some of the old Sonars once I have x3 installed with out hurting anything?

I was actually going to ask about this myself because I know X3 is missing a couple plugins from past versions like V-Vocal.

At the beginning of every SONAR installation, there is a warning of possible loss of functionality if prior versions of SONAR are removing after installing the new version. The time to remove old installations is before installing a new version. FWIW, removing a version of SONAR frees less than 200MB. Most of the disk consumed by SONAR is shared between versions. Over half of the space used by a full SONAR Producer installation are the samples included with DimPro and the "Loops and One Shots" library.
 
That said, older versions can be removed. It may be necessary to re-run the X3 installer to get some shared utilities back. It will also be necessary to reinstall X2 to get V-Vocal, should the plug-in be needed.  There are also some plug-ins unique to old versions of SONAR which can be recovered by running the old version advanced install option.

scook is steering you both in the right direction.
 
I have X1 (32 & 64), X2 and X2 (both 64) on the same machine. Only reason I don't have any earlier versions of Sonar is because that's when I built the machine, when X2 just came out. So I only install X1.
 
Not really much benefit of removing older versions.

I agree.
 
Leave all older versions on your machine.
 

1. You'll kick yourself if you remove a version and later discover certain projects report missing plugins
2. The amount of disc space you reclaim is miniscule. If disc space IS a problem, you need to invest in larger drive(s)