I would pull out the Twin Yanmar 64 hp naturally aspirated generator engines that are in my boat now, and replace them with the closest John Deere equivalent I could find. I would also like to add twin variable pitch props for slow trolling for salmon, and keeping the engines loaded at any speed. I would hope that the newer engine would burn cleaner and cause less air pollution, be a little smother, especially at low idle. I would also think the turbo would make it a little quieter.
About a year later when I started having problems with the electronics, the fuel pumps, the turbo's etc... I would deeply regret the whole thing and wish I had my simple old engines back.
Well put!
KISS!! Is the best way for most marine instances.