OK, long title, but it sort of makes sense. I have recently replaced my evaporator, and thus volunteered to help a friend replace his. I remember one tough area was to get the air box separated from the air ducts, and everyone warns about breaking the center support. We discovered that the center support can be removed, thus making the removal of the air duct easier. The center supports are tapered, and what is even more interesting is that the one in the drivers side duct is longer than the passenger side. I have tried to find a reference to these pieces, but it seems to be a secret.
Has anyone else noticed this?

Emerald