All motors are nearly equivlant, especially if you stick with the good brands. Having a good esc is truely the way to go now a days, becasue you can adjust timing, voltage, and a hand full of other useful things electronically.
I have had great luck with novak velocity motors and the tekin redline motors. I ran both with a gtb and both with the rspro, and noticed a big improvement with the rspro, with both motors geared the same in the same buggy.
The only motor that I owned, that I didnt like was the x-11 vector in 7.5. It ran hot and was noisy after a short time frame.
If I were to recomend you a motor, that I would buy, I would sugest the Redline 13.5 or the Novak 13.5 either velocity or ballistic.