The US wiper motors work for the Euro wipers on the W124. Should be the same on the W126. I would defenitely change the wipers, looks a lot better. Or you can just get the panel without the holes and leave the wipers out.
Check out this source for a good deal on the headlights:
MERCANTILE EUROPARTS Inc.
6747 S.W. 8 Street Miami, Fl 33144
Fax (305) 266-1130
I got mine there for the w124, they should also have them for the W126.