a little more info is in order I think:
1st - and this may be odd, but the battery is always dead last to get hot; in fact, it normally doesn't. It's usually, MMM, Neu, then battery gets hot. My MMM fan seems to be on almost all the time, but castle says it's ok. As for the motor selection, here's some interesting info: a VERY trusted source told me that this setup would be ideal, as Neu motors love to spin, and running mine at nearly 50k is a non issue. While they're rated to go to 60k, they can typically function up to about 100k(!). I just wanted to add a little fuel to my pending lipo fire here
Also, I didn't make my point right; i certainly notice a difference in performance between my 2 pinions: the 18T obviously has more top end, but it also seems to pull wheelies easier!

What I meant was that there isn't much difference in temps between the 2 pinions.
Does this change anything? And does anyone know where I can get tires that can stand this horribly painful abuse?