So, not to sound stupid here but this 07 9-3 Aero is first car I had that have the xeon headlights. I assume they are since bright white and self leveling? Anyways, my passenger main is getting dim. I noticed today with daytime running and then this evening when dark. Is this a sign bulb going bad with these xeon's? And if so, best choice to get or part number? Also, are they hard to replace? Sorry for all the questions. Any input would be great. Thanks!