I've searched a bit but could only find vendor in Australia or Hong Kong

http://www.naviplus.com.au/#!Mercede...f21d84af51e990

http://www.seicane.com/8-inch-2014-2...ne-canbus-8508

I've found installation instruction but only for different model.

http://www.seicane.com/mercedes-benz...er-manual#tab3

Does anyone know how to install such upgrade? Or any shop can do this professionally?

What would happen to warranty?

Thanks

I don't know about your first points, but it would be fair to say that MB would wash their hands of anything remotely connected to COMAND, from a warranty point of view.