Chevy
But then I import a specific 2 track into Ozone 7 standalone, and listen. It's quite a bit brighter and also louder than the exact same 2 track imported into a fresh Sonar X3 Studio project,
Ah. Louder as well as brighter.
What is your listening volume? Have you measured it? I ask because there may by psychoacoustics at play here.
The way our nervous system works is that at lower volumes we perceive less bass and treble, more mids. This is good because it means the most important part of the audio range is the most intelligible to us at lower volumes. It is bad because if we mix or master at too low a volume then we are not hearing the full audio range in a balanced way. This is called the Fletcher-Munson effect after a couple of people who researched it.
Make the audio louder and the Fletcher-Munson effect lessens. So we perceive more treble and maybe more bass.
There is also another psychoacoustic effect that if we're played the same track twice, but one play through 3dB louder than the other, and asked to say which we prefer we are very likely to pick the slightly louder one as best. A tendency used by unscrupulous hi-fi retailers almost as long as there's been hi-fi and also the origin of the "volume wars" in mastering.
If the output from Ozone measures higher in either peak or RMS than the output from Sonar I suggest you double-check there's no processing hapening in either, use gain addition or subtraction somewhere in the playback chain to equalise the volumes if necessary. Then turn up the monitors a bit and try comparing the results. It would be even better if it could be done as a blind test, so you don't know whether it's Sonar or Ozone you're listening to.
(Edited to add)
This can be one of the times where metering outside the DAW such as in the audio interface's mixing application can be extremely useful to check comparative levels. Ears and brain can and will be fooled, meters not so easily.