Thanks and New Brushless comments

[ICUBoy]

I just wanted to say thanks to all on this forum for the info and inspiration to add brushless to my Emaxx.
I added a Feigao 8XL, MMax ESC, UBEC, tiniest pinion I could buy, and (given what I read here) built up two 5S1P A123 battery packs (complete with copper braid upgrade!).
So it all went together OK- the batts don't sit well on the standard chassis but some zipties helped.
The MM fired up OK even on the voltage from 5S (16.5 or so), as long as I turned on the UBEC and radio first. I thought I'd take it for an uber-gentle trundle as a "proof-of-concept".
Ready
Set
1% on the trigger: a nice smooth start
25% on the trigger: ZING! CRASH! The maxx flipped over in its own wheelbase and smashed a couple of shock towers. Batts spread everywhere. ESC off the velcro. Wiring looms like spaghetti. WOW!
THIS is POWER. I thought it went well on 16 cells/Titans but this is undriveable for me (at least in my yard). I cobbled it back together and couldn't use much more than 15% trigger travel or the damn thing just flips.
I'll fix the towers and get a new chassis, and try it in a big space- what chassis do you think is safe and not too dear?
Thanks again for the inspiration, brushless is Big Fun!