I am guessing you are after speed and by the sounds and the looks of it you are a newb. I strongly suggest you go with Castle MMM ESC and 1515 1Y motor combo. You can stay with the XERUN 150A but everything is plug and play if you get the Castle combo. That should get you going in the right direction although your batteries are a bit of a worry. I guess you could use them with the Castle combo but they might be a little heavy and unsure on their C ratting. What you want is a 6S lipo with that setup and motor for ultimate speed. Something with around 5000mAh capacity and the discharge ratting of no less that 30C (but more the better) is what you ideally want. Your current batteries might do the job but IMO they are a bit on the heavy side.