The noise "problem" was not a problem when these sets were designed and built. The muffler systems for the MEP-002 all the way to MEP-007 all left something to be desired. The TQG series were the first attempt to fix the noise problem. They were much better, but still not the best solution. The new AMMPS gen sets will definitely impress you.
Something along the lines of Dependable's solution makes a big difference. But as previously stated, The mechanical noise is considerable.
The germans forced us to spend mega bucks in the early 70's to reduce the noise from our missile site. It was money that should have simply been burned for all the difference it made. We did achieve a noise reduction. But I think our mistake was to install secondary muffler systems IN ADDITION to the primary muffler. Even at, or near full load, we had wet stacking problems. I don't know how much it would affect you with a MEP-002 or 003. We were running 45 and 60 KW gen sets, 24/7 all year long. Would be interesting to follow it up. Please someone keep us posted.
The old gen sets were so loud, that back in the day, we located our missile site in the field at night, by simply parking and listening. You could always tell the difference in the different sounding gen sets, as to whether it was a HAWK site, or a COMMO site, or a Maintenance site. And I mean from 2 miles away.