Check the startup versus run amp/KW. Most good generators can take a much higher startup than run. I think the Fischer Pandas and Mastervolts are the quietest on the market. Also look into the wet exhaust system. Makes running it in a crowded anchorage more bearable for you and your neighbors.
By the way, have you priced these yet? Are you going to do it yourself? Better budget $10,000-$15,000 dollars (with 10k being WAYYYY conservative). You will likely have to glass in a shelf, run the fuel lines (including return), electrical, etc. Major project that you CAN do by yourself, but the money may be better spent letting a yard do it for you (reputable yard, that is). Also, I STRONGLY suggest adding CO monitors downstairs in all the cabins and salon. If CO escapes inside a lazarette, it will rest in the bilge and slowly make its way into the living quarters. You cannot smell it. Chances are that if you did realize you were poisoned, it could be too late. We almost lost some good friends of ours that way.
I would have a CO monitor on my boat before a life jacket... and I cannot imagine anyone dumb enough not to go without a life jacket.
Just thoughts. You can PM me if you have specific questions.