I have looked at several used S2000s and almost everyone of them has some mild to moderate discoloration of the plastic trim on the interior A-pillar, and on the plasic window trim on the forward edge inside (only visible when door open) of the door just above the hinges.

What causes this discoloration? It isn't super noticeable, but I have noticed a trend here.

 

I would assume sunlight causes the discoloration or it may be due to the fact that they didn't detail that part of the interior. It might be cured with some interior cleaner, like Finish 2001, or Black Magic.

 

lack of sunscreen (i use vinylex which has a sunscreen in it)