I am eyeballin' a used boat. My little Osprey is getting even smaller. (Could be the kids are growing) It has a 1998 KAD 44 in it.400 hours. It is in a 27 Pilot house. I realize that this has higher HP and that power wouldn't really be an issue. But how reliable have these been? Does the new ultra low diesel effect them negitively even if I use additive? What could I expect for economy at a easy cruising speed? Any help is appreciated.