You will get faster laps because of your driving skill, not because you suddenly go from a .15 sec to a .10 sec servo. They only real time I noticed a big difference was from a .22 servo to a .08 standard servo, and that initially felt very twitchy till I got used to it.
As for specs on the mamba max, look at the rating of the servo at 4.8V . I believe that is what they list them at.
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