Depends what you want.

In my case, I wanted a minimum of stuff sticking out of the cowl. This plane was designed for a .52 fourstroke, and the only thing sticking out of the cowl on mine is the muffler and the wire for adjusting the needle. Mine's, what, 4 years old? And it keeps getting better & better. After 250+ flights, it will do adequate vertical for me, and even hover a bit. I don't do 3D, but this one will hang on the prop for several seconds. A 3D flyer could probably hover it.

I never wanted to go fast, and I don't think that's the object with an Ultimate. The .46 2stroke sounds like a lot of power to me, and the muffler sticking out would be bulky. But that's just my taste.

Good luck,
Dave Olson