realize that the moment you color the pilar covers and headliner a dark color that it will toally alter the "feel" of the car. your spacious xB will become a small dark cave. when I was in college i got the bright idea of painting my bedroom ceiling dark blue. it had the effect of making the ceiling look about 12" lower, and was a little unnerving. it took my parents a long time to make it totally white again after i moved out.

of course, some people like caves...