i had two kaos .40's. a bridi kit and later the tower kaos arf. the kaos is old but great flying design. the guy that designed it back in the 70's got the numbers on the wing just right. even with the thick wing the kaos is fast with a .45 or.46. it does not need anything bigger. but it will slow down to very nice landings. the tower kaos arf has a wider fuselage than the older orginal kits to handle the newer engines. a flying buddy of mine had one of the last great planes .40 kaos's from a kit until he lost it to radio failure. a few weeks ago a guy showed up at our flying site with his old rc stuff to sell. he had a great planes kaos .60 kit. someone gave him $50 for it. looking in the box it reminded of the many kits i built or the last 25 years....but like everyone else i got spoiled by arfs.