Hi, headlights emitting different coloured lights can become a problem during the checkup.. someone I know removed the stock lights and installed blue halo / Angel lights. he was asked to revert back to stock headlights. Someone else had gotten racing stripes done on his car. he was asked to remove that during the inspection. But then again, I have heard that some testing centres are more stringent than others. Either way, fog lights and interior changes should not be a problem at all.