I would find a stronger rear end to use. That axle is made to power an extremely light truck. That 2 stroke is heeeavy and makes a lot of torque and I dont think the axles, rear end, suspension arms, etc are going to like it

Check out this thread. Several guys converted their t-maxx's to 2 strokes and had good luck:

http://www.rcuniverse.com/forum/m_2893529/tm.htm

I think you should buy a used roller, 1/8 scale MT like a savage, MGT, or Losi and convert that. The driveline should pretty much hold it, and the suspension, tires, etc.. will handle the weight much better.