You will also have the collective wisdom of the forum community ready and willing to assist you along the way, should you have questions, concerns, or issues during the install/upgrade.
What version of Windows will you be loading the Sonar upgrade into? I ask this because you should make sure your audio interface has drivers in production release that work in that version of Windows.
It is quite natural to contemplate life in the decision making process to move to a new version of Sonar.
There will be a learning curve, but you are already exposed to the UI redesign from X1d, so for that you are ahead of the game.
Lastly, there is absolutely NO need to remove X1d prior to installing the new version, and the two versions will live cheerfully alongside each other. I have X1d, X2b, X3e, and Platinum Dorkchester. I will likely be removing X1d at some point coming up, as I just don't use it anymore, and I am not going back to any projects from X1d for anybody else at this point.
(If I have reason to believe someone has a project I built for them in a prior release, that they still need to go in and do something in, I tend to finish those projects in the same release I started them in. It is not a Sonar requisite to do this, but I also never ever run into any weirdness from loading and working on a project from a prior release in a newer release - even though I have never seen that happen either).
Bob Bone