I'm using whatever it came with, but I plan to use 100k in the center with 5k rear and 7k front. BTW: 100k is not a typo.
A 2650kv motor on 4s would be ballistic unless you gear down a lot. 3s would be more driveable. I ran for 30 minutes straight on a 5Ah 4s pack with my Tekin 1900kv (buggy) system (geared 52/20) at the track tonight.