Pred, without being an expert on the subject, it appears to me the most economical means of producing higher flowing injectors is low impedance, while Nissan use an ECU that favours high impedence or lower current handling transistors.
Waldo, just use a multimeter to measure impedance (ohm symbol or the horse shoe shape) then calculate the correct resistor to bring to the correct value of between 12-14ohms.
Given the cost of the resistors is about $6 I'd say even $130 is a scam.