Wow... my probs with X1 are limited (so far) to older projects and I'm certain it ties in with getting 32 bit plug ins to work. Solution here was to use 8.5.3 for the older stuff and so far, X1 is working fine on the new stuff... hope that continues too coz I'd hate to crash the sessions with the new band in the room!! [:0]
Poppa if you are getting issues like that, I'd suggest trying 8.5 if you have it... not sure a new s/w platform is going to be any easier than getting a work around like 8.5.3 which is quite stable. This of course is assuming that the issues are not something other than Sonar of course.
The problems should only start once the mixing begins which is when the VST pain starts but assuming your pc is well, this should give no drama to you. I'm doing that very thing here with no issues with the 700 R & C gear and X1 with latest patches.
Hope it works out ok for you.