Replacing the fan(s) really isnt that hard. I had replaced my radiator, condensor, and fans on my 400E (same setup) a month ago when someone backed into my car. I did it all myself, VERY simple. You have to take the radiator out first, which requires the shroud to come out. Its a 2 piece shroud, kinda tricky cause its so tight in there, but not too bad. The radiator is simple, just remember to undo the 2 bolts on the bottom of it that secure the transmission cooler line to it. There is a drain on the radiator, front pass. side. You can turn it with your finger or a screw driver to drain the coolant.
The worst part is taking the condensor out, because your gonna have to open the AC system up. But, you have R134A from the factory in there so you are at a big advantage there. Whether you want to have the system vacuumed out by a pro or do it yourself (its enviromentally friendly) is your call. Me, I would just let it drain. Be careful not to bend or break the condensor fittings when you disconnect them. They are very fragile and flexible. Use two wrenches obviously. When you get them off, unplug the auxiliary fans (one plug, by the AC drier). The fans are actually mounted to the AC condensor, so it will come out as a whole. Its pretty straitforward once you get in there. Once you have the condensor out, mounting and unmounting the fans is self explanatory. Clean out all the debris being them blocking the fins. Also, replace the 2 green seals for the connections to the AC condensor. I received mine from NAPA, had the OEM size and fit perfect.
I forgot to mention, on both the radiator and condensor, there are 4 clips (2 a piece) that secure them to the front radiator support. When it comes time to remove them, use a needle nose pliers to large flat head screw driver. You will see what Im talking about. If you have any questions let me know. I dont think I forgot anything. Hardest part is probably the fan shroud.
93 300D 2.5 Turbo, Black/Palomino 273K
09 E350 Black/Black 41K