Alcarafa, I have the Tower Kaos & flew it for a year with an OS .40 LA. It was an OK flier with the .40 but ended up at full throttle most of the time. Over the winter months i got bored and decided to recover it and install a OS 55AX. It flies fantastic with the 55. The only mods i made to the plane were to finish off the nose section & blend in that area twds the spinner. I also moved the canopy fwd approx 1.5" because mine did the Kaos tail wag with the canopy in its stock location. After moveing it fwd the wag has dissappeared. I use the plane as a practice plane to fly my IMAC sequences at a field where my larger gas models are not as welcome. I am not a seasoned pattern flyer, but for a $99 ARF with a little work it sure flies great. Hope you get as much enjoyment out of yours as i do mine. I will have it with me at the Vintage R/C event in North Carolina this month......Gene