I'll convert you to the BLUE side yet!!!
On side a note, the Duramax or similar small V-8 should in theory make a great engine but they are just not designed for that mid-range market place, no matter how much you modify them, they are a "light" duty diesel. Second the marine market for performance diesel in so small that for other than promotional write-offs it makes no sense for any "engine" company to build them. You look at Mercruiser with all their resources is still not an engine company, they are a marinizer of automobile engines. Mercury choose not to build a diesel engine but instead turned to Cummins for a base engine.