The Mamba Max will easily do 4S, provided that you disable the internal bec. Other than that, the only limitations on the MM systems is the rpm limits of the motor, which is 65,000 rpms.

I was running my system for parking lot drag racing. I rarely got to full throttle so the motor never wound out. I was relatively comfortable running the setup because Castle tests their motors to 80,000 rpms.

I do have to say that getting it to run reliably was tough. As I said above, it was a PITA. I had to run the shortest tires that I could get. I think I was running Speed Hawg tires with two layers of duct tape on the inside to stop ballooning. The tires are meant for going fast and not general bashing. I'd only get one or maybe two nights of racing out of a set.

I used the largest spur gear that I could get with the smallest pinion that I could use while still getting a decent gear mesh. It was fast. Very fast. At those speeds you really have to take measures to keep the truck on the ground. I always ran with a body and attached a wing to the front of the truck. Weights won't do it.

If I had it to do again, I'd go for the 4600 or 4S. It will tolerate more gearing. For that matter, so will the 5700 on 3S, which is within spec for the system. The 4600 on 4S and the 7700 on 3S are both out of spec and not covered under warranty.