My Opinion is....and it is just "my opinion". There is NO definitive answer to this question. There are opinions. For instance, I've had many folks tell me our 9.9hp is way too much and too heavy for Daunltess. Fact of the matter is, that is their opinion which is fine, but let's face it everyone has one. One thing about a larger outboard is that it is a lot easier on the engine itself. Rarely do you call for full power. I guess I am not a purist, but rather more practical. I don't pull the outboard off the transom to get that extra tenth of a knot of speed, and I don't worry about the extra weight back there as long as it's not ridiculous. On "Big D" I have rearranged other stores and equipment on the boat to offset the engine's weight, and yes it's a heavy engine. The downside argument then is that you are promoting hobby horsing by weighting the ends of the boat...maybe....or you are going to break off the transom or delaminate it....maybe.....but I haven't seen that happen if proper backing plates and weight distribution are in place. Maybe it does...again....just my opinion. I CAN tell you this though....like Neil says, a lot depends on the location and conditions in which you sail. I got a good taste of "Holy $hi#!! I am glad I have this power!" motoring through the Samsung Narrows...and also on the way to Catalina Island, when we had to motor the whole way, both ways (ugh!) I was thrilled that the old Yammerhammer was just loping along a less than half throttle for the 6 hours each way. There IS something to be said for going as light and low powered as possible. No argument that if you are looking to derive the absolute top performance under sail, and go absolutely as fast as you can in a sailboat, then a large outboard hanging on the transom is not going to help you at all. But then, if you are looking to go strictly ALL OUT for speed under sail...you probably aren't reading this post because I would expect that you are on the J-boat forum. The market here is Cruiser/Racer...with the emphasis on cruiser. But it all depends on what you are interested in doing. The only person that can give you the definitive "right" answer for you......is you. If that extra horsepower makes you feel more comfortable....go for it. If not, ...don't. I did. And I am happy with my choice for me. I think as long as the majority of the sailing I am doing is cruising type sailing, I would always opt for the option of power at the upper end of the scale for the boat involved. If I was merely motoring in and out of a slip on a local lake all the time, or racing was my top priority....then that'd probably be different. Something to think about. If you and a friend were in your 15 and you each had a gallon of water...would you tell him, "Hey! do not bring that gallon of water to the back of the boat because your gallon, plus my gallon weigh 17lbs together and that will slow us down. If so , you better go light or you are not going to be happy. If you never ever gave that a thought....you won't notice the extra 15-20lbs in the back on the transom. And yes, I know...the weight off the transom has more effect because it is further from the center of the boat.....but still. You gotta evaluate what type of sailing you are doing, the conditions you are doing it in, etc. If your goal is to race the Cruiser Challenge and win....then you might have to consider the lightest motor possible, and even removing it from the transom under sail, because in that scenario, racing has taken precedence over everything else and that's what similar boats are doing to gain even the "slightest" competitive edge. There is no one right answer to the question. and that opinion is worth exactly what you paid for it!!! LOL Sean M23 "Dauntless" M17FD "Sneakers" www.saildauntless.com www.sailhavasu.com