hi there everyone...
i had originally registered to this forum just to post a comment on lutach`s thread, but since i registered, i thought i could chime in and drop my 0.02... :)
since i am new to this forum, i am completely unaware of each individual`s tempos,ideas,likings and such... so in case anyone already knows the stuff being typed below [or disagrees with it], please don`t take it personally...
i think your ammo is partially demagnetized. 'higher than before' rpm [as you put it] and elevated temps [low efficiency along with quite high currents] is a clear,solid indication of this... so essentially, you can say it`s not a 3300kv anymore... a round speculation about the 'revised' kv rating wouldn`t be much difficult to guess/estimate either; if that`s a question troubling you that is... so let`s just say that this isn`t a sharp head-to-head comparison between those two motors...

try contacting tower; they might get you a replacement...
as medusa motors are 4pole motors, it is necessary that the timing is set above 10degrees... the slotted stator design makes it even more necessary... if i were you, i would be running a medium to high timing setting on the MM, and would definately avoid 'low' or 'lowest' settings... 15 degrees is a mediocre setting for a 4pole motor [unless if it is high-kv compared to it`s physical size], and typical settings for the particular genre of motors usually float between 15-20degrees; meaning that even the stock '10 degrees advance' of the MM is quite low for the particular motor...
btw, 3300kv is a bit high for the emaxx imo... that poor ammo would stand a chance if it was a 36-56-2700 or even better the 1800...
*ammo motors on the other hand are rather touchy with the timing... lowest timing on MM should be considered mandatory when running an ammo...