Imo the mamba shouldnt be pushed at 5s or 16 cells.
I agree totally. In reality, I wouldn't go past 4s or 14 cells. Just the caps alone on the ESC are only rated for 25v and 5s is 21v on a full charge - a little too close for my liking and longevity.
Heck, you might be fine running 16 cells - I personally wouldn't for the reason stated above. I like to keep my best-case (meaning highest possible voltage off the charger) voltage at least 25% lower than the component max ratings. That puts it to ~19v max if the caps can be used as a guage. Who know what the other components are rated for...