[jollyjumper]

the g-maxx is also extended over the 2.5 chassis.
you can use the stock chassis with mike's 3 piece motor mount for the original transmission.
or hack in a e-maxx trans.
but since you wanna race i recommend using a center diff.
can do that with the nitro trans, there is probly already a diff in there.
(not sure on that as i'm no big traxxas lover)
or with the g3r and the slipperential v2.

bout the motor and esc, the quark is a good choice, smooth, runs any motor, ...
but it needs cooling.
with that quark you can run a neu motor, being 4 pole design they have lots of torque.
a neu will behave nice on partial trottle aswell.
it will be silky smooth.
you want around 2000~2200Kv for 4s lipo,
for 5s lipo you need around 1700Kv.
dont know much about the hacker c50.

oh yeah welcome aboard. have fun on the forum.