4s for sure. Either the T8i 1950kv or Pro4HD 1850kv & SMC 3600mAh or 4500mAh
I run the T8i and 4500mAh. I used to run the 3600 and it would make a 10 min main just fine.
Also if you go with one of those motors, get the LCG motor mount to lower the motor a few mm in the car.
http://www.teknorc.com/shop/tkr5212-...htened-sct410/