I have a brushless 3905 Emaxx. I'm just in the beginning of modifying the truck. The following has been done:
new t-maxx 3.3 diffs front and rear, traxxas bigbores (50wt) with progressive springs, traxxas cvd's, single servo steering (ace 1015), maxx roadrage tires on velocity 6 wheels,
HW ezrun 150A esc with a robbe 3650/04 motor, gearing 17/68 powered by two 2p2s 5100mah lipo packs, traxxas alu hex hubs.