To make a long story short, it works like a charm!
Ever since I saw the new M6 steering wheel, I was totally fascinated about it and wanted it to be retrofitted to my 2011 F10 520D. I did some research. There are some successful retrofitting cases for F10 M5/F06 5GT. No one has done it to a non-M5 F10. So I will take my chance. First I ordered the steering wheel without vibration and heating modules. This was the easy part. Next I need to buy a M6 airbag. No issue about purchase from overseas. My biggest probelm is how to ship it back to Taiwan. UPS/DHL/Fedex normally don't accept shipment of hazardous materials (airbag is one of them) for individuals so I have to use other alternatives. In the end, it took me five months for the airbag to arrive. Nevertheless the waiting is much more worth it.
I had a BMW certified maintenance shop to install it for me. Retrofitting should be easy without additional wires or coding. All buttons and paddles function perfectly, except for M1/M2 buttons which are specifically for M5/M6 but not for my 520D.
I am very happy about this retrofitting. An advice to whomever is interested: wait no more and just do it!
I am very satisfied with the new steering wheel as it completes my interior mods (for now). Here are some pictures to share. Hope you like them.