9xl, 5s, Quark 125b + Lipo battery holders?

[BrianG]

80A on 6s is around 1700w. However, you will probably be drawing around 12-15A average with peaks around 80-90A. No one pays much attention to the current ratings on those motors since car current requirements are different than flight current requirements.

As far as a special balancing lead goes, you might want to check the bottom of this page.