The top speed of a stepper motor is set by the supply voltage and the coil inductance. I wouldn’t count the PSU as key components of the linear system. The torque, and hence the acceleration, is set by the current and the efficiency of the motor. The current is under software control according to @scott.wiederhold.
If you don’t change the motor I can’t think of anything else in the linear system that would increase the top speed. A bigger pulley, but that would change the LPI and be an obvious visual difference. The belt has part numbers on so we could compare those, although I can’t see how that would affect the speed. The rails and wheels all look the same and don’t really affect speed.
So it looks to me that they haven’t actually upgraded anything and Dan has conveniently forgotten what key components have been upgraded.
I have paid a lot more for a pro partly because it has a better tube and optics. I am starting to doubt that is true. The only visual difference seems to be the slot and the Peltier cooling. Can anybody spot any other changes.