RE: Advice please
The Mustang, like almost all HZ and PZ planes, uses electronics that are not industry standard. (The Typhoon is the only exception that I know of). Although you can take all of the electronics out of the Mustang and use them in a kit, you may be better off buying an RTF for now and then flying the Mustang once you feel that you are ready for it.
You don't indicate what your previous experience is, nor how long ago you flew planes, therefore its a little difficult to know what to recommend for you. If you were starting from the very beginning, and you want to go with RTF, the best plane to start with is the Slow-V. A step up would be the pusher planes like the Aerobird Challenger, T-Hawk, EasyStar, etc. If you feel that these would be too easy for you, then go for the J3Cub or the Decathlon.