I was at a boat dealer today and I was looking at their mercury outboards. In the future I would really like to upgrade to a 20hp. My boat is rated to 15hp. I know the boat can handle even more because its in great shape. The price difference isnt too much. Would you go for 5 hp over the placarded 15? They both weigh the same too. Now my boat has an 8hp and it wont plane. Good enough for now, but im just curious.