what would be the best neu for me

[Patrick]

I would use fans on the Quark with that setup.
My e-maxx running 14 cells, 51/13 (and stock diff gears), 7xl, Quark with the heatsink from rc-monster, one 40mm fan and a 3'' fan on top of the motor and ESC, and it couldn't finish a 5 minute race without thermaling. I was told by sky & technology that I'm over geared :031:...with a 13t pinion!
The Quark is a nice ESC to drive with in terms of smoothness, but I don't really have much faith in its capabilities at the moment.