I know a lot of people, especially a lot of people with turbo lumps have done a mod to the fuel pump wiring to get the full battery voltage across the pump.
I just mentioned to someone on another list that sticking in a large capacity fuel pump could indeed increase the fueling, especially at idle because the standard fuel pressure regulator might not be able to return enough fuel to the tank to maintain the correct pressure. Someone told me that this is also something that the MkIV Supra owners do.
However, he had the chance to do this to a Supra, and stick a wide band lambda on it, and the result is that the car overfuels at idle, and struggles to get the car to stoich at all.
So if you've done that mod, you might have to increase the fuel regulator return hose size too. Or not..
Just thought it's something to think about, and I haven't seen that mentioned before.. Anyone got a std regulator with that mod, and been to a garage with a wide-band?