Do not waste your time and money with low turn brushed motors. The new brushless technology is the way to go.
A group of us here just went through this (low turn motors) and the gearing is way too tall and you will just fry the motors, (we went through the gearing thing as well) I meen melt the plastic bell right out of them! I wasted two Trinity motors this way!
I went back to all stock for awhile and my truck runs just as good as a low turn motor running a 5000mha battery, stock motor and brush conditioner. And a new stock motor is $9.00.

So, I went brushless, the Red Cat system is affordable ($120.00), durable, very fast and way more efficiant than a brushed system.

On the batterys, get the highest MHA battery you are willing to put the money out for!!!! also, do not get them hot when charging them, this will take all the snap out of them.