BMS 617DMG? Or BMS 661DMG?

Hello,
Wich of them servos is for my traxxas nitro 4 tec the best? My transmitter is FlySky FS-GT3B

Servo;
BMS-617MG+HS Super Fast Servo (Mos-FET)
PRODUCT ID: 617MG-HS
Or
BMS-661DMG+HS Super Fast Digital Servo (Metal Gear)
PRODUCT ID: 661DMG-HS

Wich is the best for my car?