looking for speedo

[steveo]

i have a hacker motor and had a hacker controller, its the set up hacker had for the e-maxx, an 8l i think the motor is, any way i burned up that speedo, that combo always ran real hot, but speed and power was unstopable, so i've been reading the hell out of these forums and have come up with two possibilities, a quark 125b or that mgm 160 amp 16 cell, i here good things about the quark, but haverent heard anything about the mgm ,i only run 12 cells and would a ubec help out also, i dont want to see any more smoke its two expensive, gearing wise i ran 18 - 72

one more thing my brother just got a 7xl and 9920 what gearing should he run, its set up with a 16 -72 out of my truck just to get him rolling, but it gets rather warm and not the fastest,

thanks, you guys know yor stuff.