No improvements have been announced for CD burning in X2. SONAR's built-in CD-burn feature isn't recommended for final burning, just for quick test CDs.
Almost any CD-burning program is capable of creating a Red Book CD, but some make it easier than others. Nero will do it, as noted above. I used Nero for years, but it had some annoying quirks that eventually drove me away from it. Nowadays I use CD Architect, and as much as I despise Sony as a company I have to admit that CDA's the best application I've found for burning audio CDs.