I think it will be.. There's been talk of "synchronizing" issues if both motors aren't correctly within phase and rpm of each other. I did a dual Castle Creations Mamba Max 5700 combo in an Emaxx awhile back that literally twisted the plastic driveshafts around like a straw. Before doing that, there were no significant heat issues on one power system over the other, and I'll confess to doing torque wheelies at 60km/h to bring on the said propshaft damage.That would be nuts! Dual 1717's.
That was way back when the MMM was having it's growing pains much like the XL2 is having now. Once the MMM's problems were sorted out, I went to a Hacker C50 and left it there. Crazy power still, but not nearly as violent as those dual 540's.