Hi-I have done something very similar. I have a 1jz swapped into my mk3 supra, it was a japanese only engine. It uses the same style injectors as the 2jz. My 1jz uses hi impedance 370cc stock injectors. The us spec 2jz injectors are a straight drop in for the fuel rail, and are pretty cheap used for a set of 550cc. That is what I'm using now. You need to use a resistor pack to get it to work. The ecu doesn't need to be modified. From what I've been told, all toyota ecus are designed for hi impedance injectors, the ones that use low impedance ones have resistor packs(outside the ecu,usally in the engine bay) Many toyotas have these resistor packs. I used the same one my old 7mgte engine used. The 1jz and 7m both batch fire injectors in pairs,so it was a perfect choice. You may want to use it or the 2jz one, depending on how the ecu contols them. What you have to do is run the power wire into the resistor pack, than to the injector. If you can find a japanese spec wiring diagram, look at the EFI wiring and than place a US spec one side by side and you can see exactly how it needs to be wired, it is very simple. You will also need to swap your injector conectors, high impedance and low impedance have different connectors,so you don't swap them over by mistake. If the 2jz fires injectors in pairs, I would recomend using a 7mgte resistor pack from a 87-92 mk3 supra turbo as they can be found very cheap and are dead relible factory parts. It's easy and will not damage the ecu if you do it correctly.
