You really do need to go to a 2P configuration with the A123 cells. In 1P configuration, they drop a lot of voltage under load and then can't deliver the current. In 2P configuration, you'll see a bigger difference.

As for bullet proofing the E-Maxx, it's gonna take a lot of upgrading. I won't say that the E-Maxx is a "weak" truck, but I will say that it has troubles withstanding the rigors of a brushless system, especially if you run that 9XL on 6S A123.

The Axial bead lock rims look nice, but they didn't hold up very long for us. The tires kept popping out.