i have Xerun 2000kv in mine. at an rc "meet up" with 10 people some with MCD, Savage flux, slash 4x4's and how fun, my ten-t was on the lips on all of them;) They were all talking about how crazy it was. so i wouldt say atleast 3s. i use 4s in mine. its compleatly psyko, but amazingly fun:)
http://www.youtube.com/watch?v=oazo4OqAZfw