also a person i know that was running a little rich
has the safc and i think he had 850 injectors to cure his problem i think he used the HKS Twin Power Ignition Amplifier !
im just guessing completly on this but this might help !
i wonder if it is dumping in alot of fuel at WOT. Most BPUs that I have seen as well as some single turbo supras, let out a small amount of black smoke at WOT because the fuel is being dumped in. maybe it is the same situation. maybe you need to tune the baby.