Dual install?

So I told my label I wasn't going to meet my deadline for the new album. I realized that I had started finding excuses for not working on my music, and was fooling myself that I was just busy for a while, but over time that argument didn't hold water any more, and I had to finally be honest with myself and admit that the reason I'm not working on music is that every time I go into the studio I come out frustrated and angry at X3. It's the norm now rather than the exception. And yet I've made music on Cakewalk software exclusively since 1989. But now it's no longer fun. X3 has made making music an extremely unpleasant experience.
 
So I had to ask myself what specifically is so frustrating, and among a long list of things, the number One reason is the loss of Layers. I know I know, new workflow, new paradigm, you have to learn it and get used to it blah blah blah. I did that, and guess what - it didn't stick. I am now just pissed off that Cakewalk is making me have to jump through these hoops. I understand there are new ways of working and all, but to abandon big features entirely and just expect people to catch up.... well, the blood boils. I realize that I now go into learning any new Sonar feature ASSUMING it's not going to be easy.
 
Anyway, I still have 8.5 lying around. Can I install 8.5 on the same computer as X3 and run them both (not simultaneously)? I know the projects aren't backward compatible, which is why I still need both - a lot of music was built in X3 and therefore needs to stay in X3, but there are a bunch of new songs upcoming that I shudder at the thought of building without Layers. Can it be done or am I asking for big trouble by trying to have both installed?
 
Sorry for the rant, I know this is a very pro-Sonar forum, but it's really upsetting to me.

jkoseattle
...I know the projects aren't backward compatible, which is why I still need both - a lot of music was built in X3 and therefore needs to stay in X3...

You might find that projects created in X3 actually do open in v8.5.  I've opened projects in Sonar 7 after having worked on them in X2.  Obviously you lose anything that relies on features that are absent from the earlier version.