I'm using the stock electronics that came with my trex250 super combo.   align 3400kv brushless with 15T, align 15a esc,  align 850mah 30C 3s lipo.   4500rpm is with the 15T,  its probably around 4750rpm~ now since i've installed the 16T.   it sounds very busy.

[youtube]http://www.youtube.com/watch?v=oho8kjzHS_I[/youtube]</p>