Glad you're willing to give 4S a try, I'm sure you will find it thrilling.
I've had the chance to run really fast setups on both a 4wg buggy (kyosho lazer) and a stadium truck (losi xxxt) using the mamba max esc. The weather here is quite hot, and definitely affected the motor temps, so not all setups were trouble free.
So far I've tried the following combos:
5700kv on 3s on the buggy - I'd say the fastest, takes off like a rocket due to 4wd.
However, not a fun setup for the long term as it would eat trannys for breakfast, just too much torque for this buggy. Also had to keep an eye on gearing, proper gearing gave acceptable temps.
while the truck has seen:
5700kv on 3s (a beast, but you have to keep an eye on temps) - I killed my motor after a while, can't gear too high)
4600 on 3S, very nice setup, runs quite fast and heat is not a big issue.
4600 on 4S - very close or just as fast as the buggy... the truck was a major beast with phenomenal acceleration. For this setup you should disable de mamba max internal BEC (and use external batteries for the receiver). Otherwise the system will be too hot and bad things will happen. On this setup I used a lower ride height (specially for the front) and mounted the receiver batteries at the front to minimize wheelies. (I used a wheelie bar too). The bad thing is you canΒ΄t overgear or risk killing the motor (killed it on the third run: switched gearing, got too excited and forgot to check temps).
VXL on 4S - crazy fast setup, temps are not a problem, However it feels between the 4600/3s and the 5700/3s. I still have to try higher gearings... I'd say it's one of the ''safer'' setups to try 4S
I do have a feeling that the VXL on 3S and a high gearing could be almost as fast as a VXL on 4S without the need and weight of the external battery pack... that's one setup I'd like to try.
hope it helps
EDIT: the truck with the 4600 on 4S had the fastest top speed, but I'd say the buggy on 5700/3S had the edge in acceleration.