you could always have the speedometer checked. If the calibration is off, the shop can fix it and give you a statement attesting this. The DA would likely reduce the ticket to improper equipment (not a moving violation) and I do not believe it would affect the prayer for judgment.
I think whats going to stick her is the PFJ. Without it I would just call the ADA or show up in court, There are countless examples of worse tickets getting reduced to non moving violations.
With it, if the PFC is in the same county as this ticket, I think she is going to have to take this one on the chin.