I can't speak to the power difference, as I've never flown a YS engine - but from what I understand the 1.10 is pretty stout in a 8-9 lb airframe - the 40 would be used more in a 12-14 lb airframe. I can't speak for the Evolution, but my 26SS weighs 43 ounces with standoffs, RTF - minus the weight of the ignition pack. Your YS weighs 27.2oz according to their website. Plus you have to factor in the weight of your motor mounts, as you don't need them. if your motormounts weighed 5oz, you're looking at about 10oz more in engine weight, plus the weight of a ignition switch and ignition battery.

Biggest benefit I see, even if all performance stays the same - by switching to the gasser, your fuel costs will drop from the $30 a gallon to about $2-$3 a gallon depending on what premium gas costs in your area. And add a little more for the 2-stroke premix oil (not expensive.)