There seems to have been some type of production change with the rear part of the roof. Originally, due to some dichroic reflector effect, the roof gave off an orange color when wet. However, it seems that cars produced after mid July do not have that effect anymore. I'm not sure of the implications of that. Its speculated that the the glass might be missing some IR blocking. In the pictures below, you can see the change. The red car is a performance model built in July. Rear Window IR Blocking Coverage 100% --> 66% --> 0% on newest builds.