I was right where you are a couple months ago only diferance was I'm using a superstar. I went with the ax, if your worried about too much power... forget it. The first bunch of times you use the trainer you will have to run the engine rich anyway so you wont have "too much" power. I got the 46ax and it seems to be a nice reliable motor, it has not deadsticked for any other reason than no fuel, and it starts easily. I know everyone has there opinion but if you want a sure fire good motor get the ax.