What gearing are you running?
I am running the very same motor in my E Revo on 4S using the MMM. It is geared 18/52 using Mod 1 gears. Great Motor! You're gonna love it.
Oh, on the soldering inside the motor you were looking at, the factory did it.
That's a wye wind termination. They all have it.
One suggestion for your setup if you don't already have it, You need to run a BEC with that ESC on 4S.