For electronics, I suggest anything that has a small footprint and is fairly lightweight. As of now the small electronic speed controllers that fit fairly well are the lrp sphere (non-tc spec) and the Novak gtb 4 cell specific controller.

For racing 12th scale at any tracks across the nation, the power source allowed is 4-cell nickel metal hydride battery packs. There is no lipo equivalent to 4 cell. 7.4 volts is too much. Past history has proven that.

Best brushless for a beginner in 12th scale is probably going to be set per track, and your best bet would be to go to your local track where you will be racing and find out what the classes are like. Most tracks that are racing stock class are running 27 turn motors with 17.5 brushless..

good luck