My throttle and steering servo are the Robbe/Futaba S9402.. Yes, analog, not digital.
Why not digital..
Well, because a digital servo draws more current from your battery pack...
A digital servo will draw maximum current always, until it reaches it's desired position, while a analog servo will draw maximum current while traveling to it's position, but less current when it almost reaches it's desired position.
So escpecially for your throttle servo, while under breaking, a digital servo will draw a lot more current than an analog one....