Three years ago, I bought a1989 Ocean Alexander with twin DD 8.2, normally aspirated. They had about 3000 hours on them, and I've put about 1200 hours on them. I treat them VERY gently, running them between 1750 and 1800 rpm. I've had 0 problems with them and the oil analysis has always come back with nothing unusual noted. When I bought the boat, I had the same concerns as you. Another person on this forum acknowledged the concerns but advised me that if the engines surveyed well, not to let them stop me from buying a boat I otherwise would like to have. So far that's been good advice.