Well, one thing I am learning from this thread is is that the current crop of 4 stroke engines are way more powerful than I had thought. When I was first involved in RC, the general consensus was that you needed almost double the capcaity to get equivalent performance from a 4C.
Now, it seems that the current YS 4C engines compare power wise with an equivalent capacity 2C engine!!!

I hate to say it, but I'm swaying towards the 110. Not that that's a bad thing, but it is straying away from my plan of building one of the aircraft that I aspired to own when I first entered this hobby. The YS 110 just seems to be such a good engine.