I'm looking at the 500 hp versions of each engine. Only putting about 200-300hrs per year on engine, so longetivity isn't a big issue with me. I've heard the 8.3 Cummins may be a little quieter, it weighs about 100 less pounds, and is slightly cheaper, though not by much. Even though those aren't big advantages, I'm leaning towards the Cummins over the Cat. Service where I'll be using the boat is comparable. So, does anyone have good reasons to go with either engine? Right now, they both seem so equal, I'll probably go with the one I can get cheaper. Any thoughts?