Ok , this question is based on my Hypothetical 50' Motor Yacht...lets call it '' M.Y. Hypo'' ! lol. Ok if I run 50' M.Y. Hypo at 1500/1800 rpm all day long cruise with either engine combo what is the comparison/differences? 1- Which engine is better on fuel? 2- Which engine is quieter of the two? No mufflers of any type. 3- Which engine is more reliable/good mechanical history record. Motor yacht wise, not sport fish wise. Please keep in mind I do not run my boats ''to the pins'' rarely over 2000 rpm. Oops except my CC Dory...I've pushed down the throttle so hard , I've bent the pins ! Thanks, I would really appreciate it.