I will say they obviously don't use that building for working on vehicles/wood work etc, way too damn clean
A Denon is no more complicated than any other modern receiver, just lousy manuals but not a whole lot worse than much of the other manufacturers. Once thay get used to it, getting the avr to work is easy and if you are not around tell them to log in here, we can always help
I thnk you are in the right direction with M3 or M22 and eD, SVS etc. for a sub; those eD A2 and A3's keep getting rave reviews and they are inexpensive.