Food for thought indeed. Thanks for that!The reason I cut the existing styrene and replaced it was so that I got the same quality of illumination in all the 'translucent' lighted areas. I tried backlighting the white styrene but it looked really very different from the areas I inserted the diffusion sheet (having a heavily yellowish cast as I recall). Also, the provided clear inserts in those areas looked completely different from the other lit areas, even when the car was unilluminated (and leaving them out would lose the flush appearance of those areas. Having places that were supposedly 'the same'on the car looking so different triggered my OCD(!) so I decided that I'd treat all the lit areas in the same way for consistency. It would certainly have been easier to have backlit the white styrene, though, you're right!