I wonder if anyone out there is driving a FRED (front engine diesel). We drove a 2007 Tiffin Allegro with a front engine Cummins. It wasn't as loud as I thought it would be. It has a lot to offer and ...
I do know someone who has one, and they really liked it. He got really good mileage with it, and liked it a lot. His prior RV was a E-450 with a diesel engine and it would have been pretty noisy. He said his FRED was pretty quiet. The larger engines have a low RPM and don't make a lot of noise because of the low engine speed. Still the turbo noise will be there.
Good luck with your decision to buy a newer motorhome!