Saito 100 is okay. I have it in my UCD. Vibration is not bad at all. The vibration shakes the plane most at 1/4 to 1/3 throttle, after that the amplitude is not bad at all. I guess UCD's resonant frequency is about 2000 ~ 2500 (divide the 1/4 throttle rpm by 2 for 4-strokes).

The only thing that came loose was the landing gear and the former in front of the wing.This you really have to add triangular stocks.

Now, if you are thinking about a Saito 180, then it's a different story.