Swamp RX-7

Hey guys, I know I'm being redundant with all this air pump crap, but check this out. If I get a Super AFC, or HKS AFR and use it with my G-Force Reprogramed ECU, would it be a good set up? I'm not trying to add more fuel at full throttle I have plenty of that for my mods. I'm trying to lean out the mixture at idle because of the lack of an air pump. I will be getting a midpipe. The thing is, I see that the S-AFC only works in 500RPM incriments, does this mean I won't be able to lean out the mix at idle? Also, if anyone knows this, how would a piggy-back FC be able to do anything at idle? It's my understanding that the ECU is using a base idle map. If this is true, than a piggy-back FC that manipulates the MAP sensor reading would not work because the ECU is not even looking at the MAP sensor, it's using a pre-programed map. Is this right? Thanks in advance!