The Kaos flies very well stock. But, I have cut the height down on the vertical fin by a couple of inches and increased the width to make up for it. I did the same for the rudder just because I thought the original vertical looked odd.

Having said that, you need to provide more information. What Kaos kit are you getting? What size? I'm sure you could figure out a way to stick a Moki 2.1 on the nose of a 60 sized Kaos, but I wouldn't advise it. These models don't take a huge amount of power to make them fly really well. Be careful with larger than called for engines because you could very well do nothing more than increase the weight of the finished model without any real gain, maybe a loss, in overall performance. In pattern or sport flying, there's no need to change any of the control surfaces. The control surfaces are just about perfect as they are stock. The Kaos is pretty sensitive to elevator as it is and has plenty of authority with rudder and aileron as well. There's no need for mixing as the model flies straight as designed, but again, this can depend on which kit you are getting and how well you build it. There's no way to tell what, if any, mixes your model might need until you fly it which is what you should do on any model before getting carried away on the setup.

I've had two GP Super Kaos 60's and currently have a DC Ultimate Kaos. All have been fantastic fliers with Ultimate Kaos being a little faster and smoother but also more difficult to slow down on landing.

John