MP-6 speed control

[DLS II]

Hi, I will soon get my MP-6 buggy back from Monster Mike. He installed a Rimfire 42-60-600 outrunner in place of the center diff. I will be running it 5 or 6s A123. The KV of the motor is 600,max constant current is 40a and max surge current is 70a. There's no telling what the spikes will be. I have on hand a Schulze 18-61K and a MM. The Schulze will handle the voltage ( 18 NIMH) but it's only good for 61a continuous and 81 surge. The MM is good for 100a and I believe 5s A123, but not 6s. On the other hand if need be I will get a MMM. Any help would be great! Thanks, Don