Ive flown the Ultimate with a DA-50 I had about 80 flights on that setup. I am currently flying the Ultimate with a Evolution 58 I have about 4 gal through it. The DA- 50 would be a better choice If your not a more experianced pilot Being a lighter Engine than the 58 The balancing is easyer on the 58 I have the rudder servo in the tail as well as the batteries and regulators to achieve a 6-3/4 back from the leading edge of the top wing { 6-1/2 being the recomendation from Tom } I had to add a little weight in the tail. With the DA the plane was a tad easyer to slow down for landings it was a tad more stable but even with the 58 it does a rock solid elevator and hairier but you have to watch for rocking as it can rock its wings but you almost have to start that rocking yourself. With the DA it just refused to rock. The big advantage of the Evolution 58 is obviosly Power the plane is not light and the extra power is more than noticable. the plane will just yank out of a hover it will swing a larger prop {24"} and larger blast patterns mean better control at zero air speed so the added weight is almost unnoticable when your hovering around you can make turns on a dime you can stop this plane dead in the air and power into a hover at will going from an elevator to a hover is a nobrainer. The down side of the larger engines is obviously landing speeds and nose overs. the bigger prop is also an issue when the tail comes up. I removed my wheel pants[&o] I went up to a 4" wheel and ive moved the CG back 1/4 from the recomended Ive been verry happy. Ive had a dead stick with both setups and all I can say is flying over the runway and over 150' is a good plan till your sure your engine is dependable this plane wont stay airborn long after the engine is out. All in all I enjoyed this plane with both setups The DA was a tad easyer to get ussed to biplanes as that one was my first. The Evolution 58 has given me a higher performance Aircraft that demands more attention. And is conciderably louder. Good luck