I've just got a new V2 MMM and Im running mine with ubec and my own fan right out of the box, it seems to hold up fine so far. I have ran thru 1 pack of 4s and 1 pack of 6s with Neu 1515 1Y, total about 40min. I did a little mod on the fan grill as well just to make sure fan blades dont get caught on it or anything getting in it, check it out here
http://monster.traxxas.com/showthread.php?t=435810