Just wanted to report back - the W210 condensor will not fit. It's too tall, even though preliminary measurements indicate that it *might* fit. Besides, the fitting configuration is totally different, though that can be accommodated with some judicious bending and perhaps one hose fabrication...

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280