Hey Soens, here's something else to try. I fought with the same problem - I tried everyone's suggestions here and on other threads I found, but still couldn't figure out why my export sounded terrible (and different than within Sonar).
I'm using a Win7 PC with x1d. I just happened to look at Properties settings of the audio devices of my system (not within x1d). Under the Enhancements tab, there was an unchecked box for "Disable all sound effects". Once I disabled the sound effects, my exports sounded just like within x1d. Also, under the Advanced tab, there were Exclusive Mode settings enabled to "Allow applications to take exclusive control of this device". This might explain why my projects sounded fine with x1d running, but not when listening to the export files.
I also confirmed that the Windows Update that I just applied today enabled that sound effect setting, so I had to disable it again after the update.
Hopefully, you'll have similar settings that will help.