964 tail lights are well known (over time) for going pink, cracking, hazing and misting up during the slightest amount of rain. My offside light got changed some time ago before I bought the car (along with the bumper corner due to a small prang) however the nearside was the original and looked like this close up:
So with the MOT looming (weak excuse) I bit the bullet and got a new one. The new ones were redesigned right at the end of the 964 production to not have a full rubber seal (vented plastic surround instead) so that the pipe from the heater blower could purge the light unit of moisture more efficiently. Up until now it seems to work much better and looks a lot better too. Especially pictured next to my brother's 997.