In my case, the brownouts with the MMP were due to the radio (Spektrum). Once I switched I had no problems, using 1258 Savox.
Ran no problem in e-buggy on 4S.
External BEC may be needed in some applications. Bit of a PITA unless you wire it to your power switch. Otherwise, you can turn off the ESC, but not the receiver, and all things plugged into it stay powered up. Alternatively, I had success with just a capacitor. That said, neither solved by Spektrum brownouts issues.
Today, I use HW SCT Pro in my e-buggy. Under $100 and zero issues. No caps, no BEC.
Last edited by rcus3r; 04-08-2015 at 08:36 AM.