Exceeding the speed limit while passing can result in two violations: (1) the improper passing ticket and (2) a speeding ticket.  Speeding is not excused merely because you were passing.  On the other hand, under NJSA 39:4-87, the vehicle you are trying to pass is not permitted to speed up or try to prevent you from passing.  In other words, police can issue a ticket to the driver who tried to prevent you from passing.