Sorry, I didn't see that you already had a resistor box. That adds the resistance back into the stock driver circuit that the P&H injectors are lacking. It just doesn't have true Peak & Hold current limiting curve. It still has the OEM saturated coil-type driver's steady, flat current characteristic.

I assume you have AEM EMS or some piggyback, since you have 680cc injectors. But whatever you have should have some provision for reading and/or logging wideband O2 (A/F ratio). If you can get that reading at several load (horsepower) points (especially the endpoints), then you could tell if you need to retune or not. A/F ratio should always be between about 15:1 (@ no load, like idle) and 11.5 or 12:1 (@ max boost).

If you still have the stock ECU with a piggyback, the stock adaptive trims might handle any small difference in flow between resistor box and P&H driver. I have no experience with EMS, so I don't know how well it's adaptive trims "learn". I have heard the "self-tuning" is limited in it's useful ability to adaptively trim to the desired A/F ratio you set for it.