i used euro parts on my US spec's E34, E39 and E53, they are all plug-n-play... I used the mirrors, I loved them... Some people used thinner glove compartment lids (less padding on euro version) for more legroom, plug and play...

Easiest way to open the mirror cover is using three plastic cards and shove them into the bottom seam between the pieces on the inner circumference of the mirror assembly... there are some write-ups about the trim removal, it seems to be the MOST difficult part of this mod...