Geistware,
I agree the 110 is more powerful It had more advanced porting than the 105 and produces more power with less weight, But like a lot of other manufactures powerful 100cc class engines one lean run and the engine is toast. The 105 is slightly heavier and less power, it has the same case and rods as the 110 and the same type but slightly smaller pistons. The only difference is the 105's have some super rugged "bullet proof" cylenders. Even if you use and abuse these engines and run them lean it will survive to fly another day. If i buy new I will probably get the 110, the weight and power is to apealing, I will just be careful on the needles and make good use of some cowel ducting.