RW Carbon = China replicas
GetBMWparts.com = OEM BMW
I have the mirror caps from RW carbon and they are acceptable quality IMO.
Here are some pics of my X5 for reference.
Carbon fiber caps by
Nam Ji, on Flickr
Carbon fiber caps by
Nam Ji, on Flickr
Carbon fiber caps by
Nam Ji, on Flickr
Carbon fiber caps by
Nam Ji, on Flickr
F15 by
Nam Ji, on Flickr
Carbon treatment by
Nam Ji, on Flickr