I will have to agree with BigNed as far as an option for this engine. The EF Yak is a very impressive candidate. For now, you have the engine and the UCD. Use it while you try to decide. I dropped in a YS110FZ about four gallons back and it has renewed my interest in the UCD greatly. I found it to be an entirely different flying experience. The 16/6 APC it will spin, enhances the performance, allowing it to bite right into a hover and really improved harriers. For some reason, the couple additional ounces up, from a Saito 100, improved handleing in my opinion. If you are looking to hang with your tail in the weeds, then you will appreciate the additional power for pulling out of a bad attitude. Check it out, you won't be sorry. Good luck, Joe