The wall connector is a separate item (it isn't part of the car per se) but I can't find any reference to the # of amps available on the converters in the car. I'm assuming same as S, but could be wrong.
Edit: the link above seems to indicate 60A, but the poster says 72A. Either way, appears there is only one choice.
Model X Signature comes with a 72Amp, gen 3 charger. The HPWC Tesla sells for Model X will work but will only draw a max of 72Amp when plugged into a Model X. My understanding is that Model X comes with the same Mobile Connector as Model S. So 40Amps