You'll need new batteries and switches.
You can get the throttle arm from OS.
Skip the power panel. Consider mounting a Lipo battery to your starter rather than using a cord and use a self-contained glow starter and a manual fuel pump. Even with having to buy a basic Lipo charger, your total cost will be near the same, and it's so much more convenient.
Do you have a good flying space, or will you need to join a club?