VM is not a great environment for running "real-time" (low-latency critical) applications.
VM may be working fine for your friend... but think about the logic.
You're looking for a high-performance system... for running Sonar.
VM is not going to offer the same level of performance as a top-quality dedicated Windows machine.
You probably already know that Cakewalk doesn't officially support BootCamp.
If this machine's primary purpose is to run Sonar, you're taking (or talking about) a very indirect approach.