There won't be options for this, but the overlay graphics used to mark active and/or hovered tabs are not final (they are basically placeholders in the current alpha builds of TabSRMM 3 to have something to work with). This will be improved a bit, probably by using Aero colorization methods. the final result should look very similar to the images you posted here - active or hovered tabs will look much more different from standard tabs and the colorization will match the settings that already exist under Customize->Message Window skin->Window layout tweaks. The tab colors you can set there will be moved to Customize->Fonts and colors

Also, the images used to skin tabs in Aero mode are customizable (or will be in the final TabSRMM 3 version). The images to skin the aero tabs are extracted to your profile and the user can overwrite them with own images. Note that this may not work in the alpha builds, because they use a force-extract method and will always overwrite the images.

Thanks, editing the image files works very well for the present.

If you do so, you should backup your modified images to a safe location. It is likely that they get overwritten by a future build.