I remember when I had my old V drive boat, there was something about insurance bet. having water cooled exhaust and non water cooled exhaust.
Since I had over the back headers (non water cooled) they wouldn't insure it,
so I plumbed in water in the collector, they agreed to ins. it after that, lol
I don't know if that's in play anymore or not, just something I remember from my boat days.