I feel for you, although on the 201, there is a sub panel in the engine compartment to access the evaporator, so its a easy replacement. It concerns me that for such an item, why MB did not have a access panel like the 201? Foolish to pull the entire dash to replace one of those.
My plastic radiator spout cracked and started leaking on my 300E also, had to replace the entire radiator. Should of been some sort of removable part instead of the entire radiator.