I noticed that it comes with optional 6s diffs, perhaps that's part of there "updated kit" !? Minimal research conducted on my part, was too keen to get the order in before they sell out
I am a bit of speed freak and I doubt that the 1750kv on 4s (motors rated max voltage) will be enough, assuming that your planing on running the 1600kv on 6s? I want mine to be good for around 60Mph.
Can you link to the motor you chose ?
Thanks