My UCD 60 has the Magnum .91 TWO STROKE and it's enough to 3D. Hovers around 1/2-2/3 throttle. Hobby People runs a sale a couple of times a year on the Mag .91 for $120. I paid $150 for both of mine and I'm happy with them.

I use an APC 14x4W prop. I found the 15x4 spools up too slow and doesn't pull much harder.

Great Combination.