Brushless Setup in New EMAXX

[DRIFT_BUGGY]

I asked the guys on the Traxxas Forum but didn't get much info only to stay away from Flightpower Batteries as they are to good.
Looking at probably putting a 8XL motor in and Mamba ESC and was looking at running FlightPower LiPo 7.4V 4250mAh Evo Lite 2S put they said it will overheat and the batteries are made with higher quality cells. They have a consistent, high, flat discharge with less reported cell puffing and venting. Which is why I can't run with them?