I bought izotope's ozone. I tried the demo (free) for several days, I was sold. I'm extremely happy with it. I'm using it for mastering with sound forge. Apparently people have been complaining about the presets, but I have used my own settings. Although it's intended for mastering (heavy CPU usage) it can be used in sonar as an individual plug in. Only those modules being used are actually draining the CPU.