I have had my Lazer 3D For 2- 3 years with silly amounts of flights on a Irvine 53 with 12,25x 3,75 props. Cant fault this combo. Gives great response. Taught me how to prop hang and torgue roll. I think that the Irvine is just about dead now but I would replace this combo at the drop of a hat. I had a madness with a YS 63 and another with a Irvine 53 Nothing in it for response just a lot more power and torque with the 63. Also a lot more expensive to run and harder on the airframe (Vibration)