ORIGINAL: hunter306
Yep, it's the E-Maxx 2 speed shift-on-the-fly transmission.
It requires two mod plates that bolt onto the bottom of the standard TXT-1 chassis. There isn't much room in there for the motors, I'll tell ya that!
I'm going to be dropping in the Novak HV-Maxx 6.5 when it comes in this weekend.
That motor is pretty big. What side you gonna mount it on? I would probably mount it on the opposite side from where the truck will be rolled from the torque. But you probably planned that anyways. Make sure you get a video of it!