It's amazing how much you wind up learning about PC's when you get into this.
When I started with this recording stuff I never owned a computer so I had to learn all this and how to use Sonar all at the same time.

Fun stuff huh?

Mike 

Fun stuff huh?

Nope.

;-p

There should be no problems installing 8.5. Your X2 installation will still be fully functional, plus you'll have the added benefit of being able to use the X2 plugins (e.g. Studio Instruments) in your 8.5 projects. You'll also get the bug fixes for V-Vocal and Sonitus plugins.

Yea Mike, I installed Sonar 7 after X1 and X2 were installed so I could troubleshoot a VST issue. I like to have one version set up without any vst so I can recover a project. No issues with X2 or Sonar 7 with the few plugs I have installed in it.

Thanks Bit and Grant.
Good to know if it comes to that.

Mike

I think it is one of the better features of using Sonar.  That it seems 100% happy to co exist beside all versions. Most software ( all others??) will overwrite and delete any older versions and automatically too! , And some would go" There is already a newer version of this software installed" and cancel install on you. 
And as a die hard 8.5 fan, I say it's still worth having it on board if your just trying to get on with it.  My take is I would need a much better computer fist before I would try and upgrade. And a few weeks of downtime to re learn a new DAW. ( I tried the x1 Trial )