RE: Ultimate Bipe engine
Agree with Chuck too. Had a DA-50 on mine. This is one of the best planes I have flown to date. The DA has a lot of power for this plane but the key items are power and weight. It is not too heavy with a 50cc engine. You still have very low wing loading. Now as far as power - you can easily manage your throttle.
A 3 blade prop would be cool but the $$$ were just to much, plus the spinner.....