I put the 160SX in it. Just before I flew it for the first time, I was worried it wouldn't be enough, but I was wrong. This engine combo is fantastic with the Hawk. If you have some extra cash to throw at it, buy the 180RX. I wouldn't put anything bigger in it. I posted a pic of the elevator servo setup.

SM has some QC issues here and there, but I believe I have addressed them during my build. Overall, this is great flying plane. It was the smoothest maiden that I have ever done in the 20 years of flying. Luck or smart engineering, the plane seems to be perfectly designed for stable, smooth flying. You won't regret buying this one.