Nice perspective. I see some complain this is not a useful review; well, I read it as an owner of the previous M6 giving impression on the new one, not a technical comparo per se and it is a good short read.
The key point I got from it and have to agree is that it is a different era now and the turbo engines is the current solution to maintain (and improve) power while meeting the drastic fuel consumption and emission control requirements. Just fact of the new global state of affairs whether we as automobile enthusiasts (some purists) like the government imposing or not.
I LOVE high revving NA engines while accepting the changing regulations forcing manufacturers' hands. So my current solution: get my S65 V8 now and keep my options open for the future. Until they stop making gasoline, we can still choose to drive these "old fashion" NA engined beasts all we want, haha...