....which ecu that is designed for low ohm injectors has internal resistors then?
if it has resistors then it was NOT designed for low ohm injectors but has been frigged to make them work.
the fact is that low impedance injectors (peak and hold injectors) are designed to be low resistance to allow for higher power at the instant they are commanded to open = "peak" and then the drive power is reduced for the "hold" part.
series resistors prevent the high turn on power making sluggish opening and also prevent the injector closing circuitry operating correctly as well, resulting in sluggish closing too = BOTCH UP.
many people apparently do use series resistors successfully but it would appear that the greater the size of the injector, the greater is the potential problem
Agreed 100% and I have designed a few ecu's in my time