scook
If you want extensive color control, there is a free 3rd party add-on Duckbar available at http://sonarmods.com registration is required to download
PGM, in my experience, Panu's Duckbar mod is pretty safe to use & will give you almost endless possibilities to change colors for the Sonar GUI. True, Cake doesn't officially support the mod, but there is an easy option to revert back to Sonar default for whatever reason. It can be a bit time consuming to learn, but there are also some color templates available including 'hit you in the face' ones that are easy to apply. Panu usually tries to keep up to date with the latest Sonar versions. If he doesn't have the one you need, he has been known to work on the version you want.
Best,
HeyDan