by the time I finished the modification, wih all the parts includin wood and glue amd misc parts I a think its about 300.00 maybe more I didnt add it up. the retracts were 165.00 the air kit was about 55.00 and the rest was misc parts the biggest thing was I had about 80 hrs in the project it tool alot of time to just figure out the way I wanted to install the retracts to make them come out just right, the rest was make things up as you go to make it function right as well as make it look good, I have made many scratch built planes, it talkes alot of research, patients ,and most of all it helps to have knowledge of all functions to the mechanics of a airplane. I have been flying real ones for over 30 years and have about 13500 hrs of stick time in many different planes (I am a retired LT Col, Air force), but most of all I enjoy building and flying models, it is so relaxing and enjoying to see the finished product, Ill post a video of the retracrs with the new and up and commig completed planes soon