Hello mate,
I'm just starting out racing with a B4 (outdoors).
I run a hobbywing 120amp V2.1 esc and an old LRP X11 8.5 motor which is a sensored system.
I bought motor on here for about £30 and the esc from giant shark for about £85. I also added the program box for £12.
I am please so far with this setup as I can dial it right down to stop me crashing quite so often.