Buy what you need for the present
I have a 26X with a 50hp. In the 4 years I have owned it, I have not had occasion to fully utilize the 50 horses. I think I have had it at full throttle only a couple of times and that was right after I bought it just to see how fast it would go. I don't know about the M, but you can make the motor stationary on the X by connecting the steering bar to the top of the rudder pivot pin. That is what I do and just use my rudders for steering while motoring up to 6 to 8 mph. No problems yet. And it steers a lot better under sail since it is not having to turn the motor while it is tilted out of the water.Of course every one has differnt ideas, but as I've said before, it's a shame that the "Big Motor" Mac owners look down their noses at Macs with smaller motors. I call them Motor Purists just like those Sailing Purists that look down their noses at all Mac owners. I didn't ask the question, but thanks to Randy for getting right to the point. And shame on me for rambling.