I thought I'd hear back from you regarding the one I was trying to unload - pity, it seems you already have one.

The bumper does NOT have to be removed. The radiator and fan assembly do, however, along with the crossmember that goes above the radiator. A bunch of rubber will come out along with the fan assembly IIRC, and after that it's pretty straightforward.

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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